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New Zealand Scholarship Physics study materials
New Zealand Scholarship Physics study resources

New Zealand Scholarship Physics practice questions

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Question 1Physics (content domains not enumerated in source)

A ball is thrown vertically upward and returns to the thrower's hand. Ignoring air resistance, which statement about its acceleration is correct throughout the flight?

  1. It is zero at the highest point and directed downward elsewhere.
  2. It points downward on the way up and upward on the way down.
  3. It is directed upward on the way up and downward on the way down.
  4. It is constant in magnitude and directed downward for the whole flight. Correct answer.

Explanation

Once the ball leaves the hand, gravity is the only force acting on it, so the acceleration equals g, directed downward, at every instant including the highest point. The velocity changes direction, but the acceleration does not.

Question 2Physics (content domains not enumerated in source)

A car travelling at 20 m/s brakes uniformly and stops in 5.0 s. What distance does it travel while braking?

  1. 25 m
  2. 100 m
  3. 50 m Correct answer.
  4. 40 m

Explanation

For uniform acceleration the average velocity is the mean of initial and final velocities, (20 + 0)/2 = 10 m/s. Multiplying by the 5.0 s braking time gives 50 m.

Question 3Physics (content domains not enumerated in source)

A 2.0 kg block rests on a horizontal surface. A horizontal force of 6.0 N is applied and the block remains stationary. What is the magnitude of the static friction force acting on the block?

  1. 0 N
  2. 20 N
  3. 12 N
  4. 6.0 N Correct answer.

Explanation

Because the block does not accelerate, the net horizontal force must be zero. Static friction adjusts to match the applied force, so it equals 6.0 N in the opposite direction.

Question 4Physics (content domains not enumerated in source)

Two isolated point charges are moved so that the distance between them is doubled while their charges are unchanged. The magnitude of the electrostatic force between them becomes

  1. four times its original value
  2. twice its original value
  3. half its original value
  4. one quarter of its original value Correct answer.

Explanation

Coulomb's law states the force is inversely proportional to the square of the separation. Doubling the distance multiplies the force by 1/2 squared, that is one quarter.

Question 5Physics (content domains not enumerated in source)

Which quantity is a scalar in physics?

  1. Magnetic flux density
  2. Work Correct answer.
  3. Momentum
  4. Electric field strength

Explanation

Work is the dot product of force and displacement, so it has magnitude and sign but no direction in space; it is a scalar. The other listed quantities all have direction and are vectors.

Question 6Physics (content domains not enumerated in source)

A wave source produces 12 complete oscillations in 3.0 s. What is the frequency of the wave?

  1. 12 Hz
  2. 4.0 Hz Correct answer.
  3. 36 Hz
  4. 0.25 Hz

Explanation

Frequency is the number of oscillations per second, found by dividing 12 oscillations by 3.0 s. This gives 4.0 Hz.

Question 7Physics (content domains not enumerated in source)

In a nuclear fission reaction, the total rest mass of the products is slightly less than that of the reactants. This mass difference appears mainly as

  1. a decrease in the total number of nucleons
  2. an increase in the electric charge of the products
  3. kinetic energy of the products Correct answer.
  4. a reduction in the speed of light within the nucleus

Explanation

Einstein's mass-energy relation E = mc squared converts the lost rest mass into energy, which appears as kinetic energy of the fission fragments and neutrons. Charge and nucleon number are conserved.

Question 8Physics (content domains not enumerated in source)

A resistor of 12 ohms carries a current of 0.50 A. What is the power dissipated in the resistor?

  1. 3.0 W Correct answer.
  2. 24 W
  3. 6.0 W
  4. 0.042 W

Explanation

Power dissipated in a resistor is I squared R, that is (0.50) squared times 12. This equals 0.25 times 12 = 3.0 W.

Question 9Physics (content domains not enumerated in source)

A projectile is launched at 30 m/s at 40 degrees above the horizontal over level ground. Which quantity stays constant during the flight when air resistance is neglected?

  1. The horizontal component of velocity Correct answer.
  2. The speed of the projectile
  3. The vertical component of velocity
  4. The direction of the velocity vector

Explanation

With no horizontal force, the horizontal velocity component is constant. The vertical component changes at rate g, so the speed and the velocity direction both change continuously.

Question 10Physics (content domains not enumerated in source)

A 1200 kg car rounds a flat curve of radius 50 m at 15 m/s without skidding. What minimum coefficient of static friction is required?

  1. 0.90
  2. 0.46 Correct answer.
  3. 0.30
  4. 0.15

Explanation

The required centripetal force is mv squared over r, supplied by friction mu times mg. Cancelling mass gives mu = v squared / (rg) = 225 / (50 times 9.8) = 0.46.

Question 11Physics (content domains not enumerated in source)

Two masses, 3.0 kg and 5.0 kg, are connected by a light string over a frictionless pulley. What is the magnitude of their acceleration?

  1. 2.5 m/s squared Correct answer.
  2. 1.2 m/s squared
  3. 9.8 m/s squared
  4. 4.9 m/s squared

Explanation

For an Atwood machine, the net driving force is (m2 - m1)g and the total accelerated mass is m1 + m2. Thus a = (5.0 - 3.0) × 9.8 / (5.0 + 3.0) = 2.45 m/s squared, which rounds to 2.5 m/s squared to two significant figures.

Question 12Physics (content domains not enumerated in source)

A gas is compressed slowly at constant temperature. Which statement about the gas is correct?

  1. No heat is exchanged because the process is isothermal.
  2. The gas releases heat while the surroundings do work on it. Correct answer.
  3. The internal energy decreases because the volume decreases.
  4. The gas absorbs heat and does work on its surroundings.

Explanation

For an ideal gas at constant temperature the internal energy is unchanged, so the first law requires Q = W. Compressing means work is done on the gas, so heat must be released to keep internal energy constant.

Question 13Physics (content domains not enumerated in source)

A simple pendulum has period T on Earth. On a planet where the gravitational field strength is one quarter of Earth's, the period of the same pendulum becomes

  1. T/4
  2. T/2
  3. 2T Correct answer.
  4. 4T

Explanation

The period of a simple pendulum is 2 pi times the square root of L/g. Reducing g to one quarter multiplies the period by the square root of 4, that is 2.

Question 14Physics (content domains not enumerated in source)

Light of wavelength 600 nm passes through a double slit with separation 0.30 mm. What is the spacing between adjacent bright fringes on a screen 2.0 m away?

  1. 0.40 mm
  2. 1.0 mm
  3. 4.0 mm Correct answer.
  4. 4.0 cm

Explanation

Fringe spacing is lambda L / d = (600e-9 times 2.0)/(0.30e-3) = 4.0e-3 m. This equals 4.0 mm.

Question 15Physics (content domains not enumerated in source)

A photon of energy 5.0 eV strikes a metal surface with a work function of 2.0 eV. What is the maximum kinetic energy of the emitted photoelectron?

  1. 2.5 eV
  2. 7.0 eV
  3. 10 eV
  4. 3.0 eV Correct answer.

Explanation

The photoelectric equation gives maximum kinetic energy as photon energy minus work function, 5.0 - 2.0 = 3.0 eV.

Question 16Physics (content domains not enumerated in source)

A charged particle enters a uniform magnetic field with its velocity perpendicular to the field. The particle moves in a circular path. If the speed is doubled, the radius of the path

  1. doubles Correct answer.
  2. is unchanged
  3. quadruples
  4. halves

Explanation

The magnetic force provides the centripetal force, qvB = mv squared / r, giving r = mv/(qB). Radius is directly proportional to speed, so doubling v doubles r.

Question 17Physics (content domains not enumerated in source)

An ideal transformer has 200 turns on the primary and 50 turns on the secondary. If the primary is connected to a 240 V AC supply, the secondary voltage is

  1. 120 V
  2. 960 V
  3. 240 V
  4. 60 V Correct answer.

Explanation

For an ideal transformer the voltage ratio equals the turns ratio: Vs/Vp = Ns/Np = 50/200 = 1/4. Thus Vs = 240/4 = 60 V.

Question 18Physics (content domains not enumerated in source)

An object is placed 30 cm from a converging lens of focal length 20 cm. Where is the image formed?

  1. 60 cm from the lens on the opposite side Correct answer.
  2. 12 cm from the lens on the opposite side
  3. 30 cm from the lens on the same side
  4. At infinity

Explanation

Using 1/f = 1/u + 1/v with f = 20 cm and u = 30 cm gives 1/v = 1/20 - 1/30 = 1/60, so v = 60 cm. A positive image distance means a real image on the far side.

Question 19Physics (content domains not enumerated in source)

A satellite orbits a planet in a circular orbit of radius r. According to Kepler's third law, the square of its orbital period is proportional to

  1. r
  2. r squared
  3. the square root of r
  4. r cubed Correct answer.

Explanation

Kepler's third law states that T squared is proportional to r cubed for orbits around the same central body. This follows from equating gravitational force to the required centripetal force.

Question 20Physics (content domains not enumerated in source)

A block slides down a rough incline at constant speed. Which statement best describes the energy transfers involved?

  1. Kinetic energy increases while potential energy stays constant.
  2. No energy is transferred because the speed is constant.
  3. Gravitational potential energy is converted entirely into kinetic energy.
  4. Gravitational potential energy is converted into thermal energy in the surfaces. Correct answer.

Explanation

At constant speed the kinetic energy is unchanged, so the loss of gravitational potential energy must be dissipated as thermal energy by friction. Energy is still transferred even though the speed is constant.

Question 21Physics (content domains not enumerated in source)

A capacitor of 10 microfarads is charged to 200 V. What energy is stored?

  1. 1.0 J
  2. 2.0 J
  3. 0.010 J
  4. 0.20 J Correct answer.

Explanation

The stored energy is one half C V squared = 0.5 times 10e-6 times (200) squared = 0.5 times 10e-6 times 4.0e4 = 0.20 J.

Question 22Physics (content domains not enumerated in source)

A radioactive sample has a half-life of 8.0 days. What fraction of the original nuclei remains after 24 days?

  1. One eighth Correct answer.
  2. One third
  3. One half
  4. One sixth

Explanation

Twenty-four days is three half-lives. After each half-life the remaining fraction halves, so the fraction left is (1/2) cubed = 1/8.

Question 23Physics (content domains not enumerated in source)

A uniform metre rule is pivoted at its centre. A 2.0 N weight hangs 30 cm to the left of the pivot. Where must a 3.0 N weight be placed to balance the rule?

  1. 45 cm to the right of the pivot
  2. 20 cm to the right of the pivot Correct answer.
  3. 30 cm to the right of the pivot
  4. 10 cm to the right of the pivot

Explanation

For rotational equilibrium the moments must balance: 2.0 times 30 = 3.0 times d, giving d = 20 cm. The weight is placed on the opposite side of the pivot.

Question 24Physics (content domains not enumerated in source)

A gas undergoes a cycle in which it absorbs 500 J of heat, does 200 J of work, and returns to its initial state. Which statement about the cycle is correct?

  1. The gas must have released 500 J of heat during the cycle.
  2. The net work done by the gas equals the net heat absorbed over the cycle. Correct answer.
  3. The internal energy change equals 700 J over the cycle.
  4. The internal energy increases by 300 J over the cycle.

Explanation

Over a complete cycle the gas returns to its initial state, so the change in internal energy is zero. The first law then requires net heat absorbed to equal net work done.

Question 25Physics (content domains not enumerated in source)

Two identical capacitors are connected in series across a battery. Compared with connecting them in parallel across the same battery, the total energy stored in the series arrangement is

  1. twice as large
  2. half as large
  3. the same
  4. four times smaller Correct answer.

Explanation

In parallel the equivalent capacitance is 2C and the energy is one half times 2C times V squared. In series the equivalent capacitance is C/2, giving one quarter of the parallel energy, so it is four times smaller.

Question 26Physics (content domains not enumerated in source)

A student measures the diameter of a wire six times and obtains values that cluster tightly around 0.52 mm, but a calibrated micrometer shows the true diameter is 0.58 mm. Which statement best describes the student's measurements?

  1. They are both accurate and precise.
  2. They are neither accurate nor precise.
  3. They are accurate but not precise.
  4. They are precise but not accurate. Correct answer.

Explanation

Precision refers to how closely repeated measurements agree with one another, while accuracy refers to how close the measured value is to the true value. The tight clustering shows high precision, but the systematic offset from 0.58 mm shows poor accuracy.

Question 27Physics (content domains not enumerated in source)

A quantity is quoted as 4.50 plus or minus 0.05 metres. How many significant figures does the stated value 4.50 carry, and what does the uncertainty indicate?

  1. Two significant figures, since the trailing zero is not significant.
  2. One significant figure, because the uncertainty dominates the value.
  3. Three significant figures, indicating the last digit is uncertain by about one unit in the hundredths place. Correct answer.
  4. Four significant figures, since the uncertainty adds an extra digit.

Explanation

A trailing zero after a decimal point is significant, so 4.50 has three significant figures. The uncertainty of 0.05 m shows the hundredths digit varies, matching the precision implied by the last significant figure.

Question 28Physics (content domains not enumerated in source)

A ball is thrown vertically upward and later returns to the thrower's hand. Taking upward as positive and ignoring air resistance, which description of its acceleration is correct throughout the flight?

  1. The acceleration is constant at about 9.8 m/s^2 downward for the whole flight. Correct answer.
  2. The acceleration is zero at the highest point and 9.8 m/s^2 downward elsewhere.
  3. The acceleration decreases steadily from its launch value to zero at the top.
  4. The acceleration is 9.8 m/s^2 downward on the way up and 9.8 m/s^2 upward on the way down.

Explanation

Near Earth's surface the gravitational force on a projectile is essentially constant, so the acceleration is constant at g directed downward during the entire motion. Velocity becomes zero at the top, but acceleration does not.

Question 29Physics (content domains not enumerated in source)

A student walks 3.0 km due north and then 4.0 km due east. What is the magnitude of the resultant displacement from the starting point?

  1. 12 km
  2. 7.0 km
  3. 5.0 km Correct answer.
  4. 1.0 km

Explanation

The two legs are perpendicular, so the resultant is found with Pythagoras: the square root of (3.0^2 + 4.0^2) equals 5.0 km. Displacement is a vector, so the legs add vectorially rather than arithmetically.

Question 30Physics (content domains not enumerated in source)

A force of 20 N acts at 60 degrees to the horizontal on a box. What is the horizontal component of this force?

  1. 0 N
  2. 10 N Correct answer.
  3. 20 N
  4. 17 N

Explanation

The horizontal component is F cos(theta), giving 20 times cos 60 degrees, which equals 20 times 0.5 = 10 N. The vertical component would be 20 sin 60 degrees, about 17 N.

Question 31Physics (content domains not enumerated in source)

Which statement correctly describes the direction of the induced current when a magnet is pushed toward a coil?

  1. The induced current creates a magnetic field that opposes the approaching magnet. Correct answer.
  2. No current flows because the magnet is not charged.
  3. The induced current creates a magnetic field that attracts the approaching magnet.
  4. The induced current flows only after the magnet stops moving.

Explanation

Lenz's law states that an induced current flows in a direction whose magnetic effect opposes the change producing it. Approaching the coil increases flux, so the induced field repels the magnet.

Question 32Physics (content domains not enumerated in source)

In the photoelectric effect, increasing the intensity of incident light above the threshold frequency, while keeping frequency constant, produces which result?

  1. No electrons are emitted until the frequency is increased further.
  2. The maximum kinetic energy increases while the number of electrons stays the same.
  3. More photoelectrons are emitted per second, with the same maximum kinetic energy. Correct answer.
  4. Fewer photoelectrons are emitted, each with greater maximum kinetic energy.

Explanation

Intensity determines the number of photons arriving per second, so more electrons are released per second. The maximum kinetic energy depends on photon frequency through the work function, so it is unchanged.

Question 33Physics (content domains not enumerated in source)

A spring of spring constant 200 N/m is stretched by 0.10 m from its natural length. What elastic potential energy is stored?

  1. 1.0 J Correct answer.
  2. 2.0 J
  3. 0.10 J
  4. 20 J

Explanation

Elastic potential energy is one half k x squared, giving 0.5 times 200 times 0.01, which equals 1.0 J. The energy scales with the square of the extension.

Question 34Physics (content domains not enumerated in source)

A sound wave travels from air into water, where its speed is much greater. What happens to its frequency and wavelength at the boundary?

  1. The frequency stays the same and the wavelength decreases.
  2. The frequency increases and the wavelength stays the same.
  3. Both the frequency and the wavelength decrease.
  4. The frequency stays the same and the wavelength increases. Correct answer.

Explanation

Frequency is set by the source and does not change when the wave crosses a boundary. Since speed equals frequency times wavelength, a higher speed in water requires a longer wavelength.

Question 35Physics (content domains not enumerated in source)

A pipe closed at one end resonates at a fundamental frequency of 250 Hz. What is the frequency of the next resonance of this pipe?

  1. 125 Hz
  2. 750 Hz Correct answer.
  3. 250 Hz
  4. 500 Hz

Explanation

A pipe closed at one end supports only odd harmonics, so the resonances are at f, 3f, 5f and so on. The next resonance after 250 Hz is therefore 3 times 250 = 750 Hz.

Question 36Physics (content domains not enumerated in source)

Two coherent sources emit waves in phase. At a point where the path difference to the sources is 1.5 wavelengths, what is observed?

  1. No interference, because the sources are separated in space.
  2. Destructive interference, because the path difference is an odd number of half wavelengths. Correct answer.
  3. Constructive interference, because the path difference is a whole number of wavelengths.
  4. Partial interference with intensity equal to a single source.

Explanation

For in-phase sources, constructive interference needs a path difference of a whole number of wavelengths, and destructive interference needs an odd number of half wavelengths. A path difference of 1.5 wavelengths equals three half wavelengths, giving cancellation.

Question 37Physics (content domains not enumerated in source)

A gas in a cylinder is heated at constant pressure so that its volume doubles. Which statement about the average kinetic energy of its molecules is correct?

  1. It stays the same, because the pressure is unchanged.
  2. It doubles, because absolute temperature doubles at constant pressure. Correct answer.
  3. It quadruples, because kinetic energy depends on the square of the volume.
  4. It halves, because the molecules are more spread out.

Explanation

For an ideal gas at constant pressure, volume is proportional to absolute temperature, so doubling the volume doubles the temperature. Average molecular kinetic energy is proportional to absolute temperature, so it doubles.

Question 38Physics (content domains not enumerated in source)

An ideal gas is taken through an isothermal expansion. Which combination of heat, work and internal energy change is correct?

  1. Heat is released, work is done on the gas, and the internal energy falls.
  2. Heat is absorbed, no work is done, and the internal energy rises.
  3. No heat is exchanged, the gas does work, and the internal energy falls.
  4. Heat is absorbed, work is done by the gas, and the change in internal energy is zero. Correct answer.

Explanation

Internal energy of an ideal gas depends only on temperature, which is constant in an isothermal process, so its change is zero. The first law then requires the heat absorbed to equal the work done by the gas during expansion.

Question 39Physics (content domains not enumerated in source)

A point charge produces an electric field of magnitude E at a distance r. At a distance 3r from the same charge, what is the field magnitude?

  1. E/3
  2. 9E
  3. 3E
  4. E/9 Correct answer.

Explanation

The field of a point charge follows an inverse-square law, so it is proportional to one over r squared. Tripling the distance divides the field by 9.

Question 40Physics (content domains not enumerated in source)

Three identical resistors are connected in parallel across a battery. Compared with a single resistor connected across the same battery, what is the total current drawn?

  1. Three times as large, because the equivalent resistance is one third. Correct answer.
  2. The same, because each resistor has the same resistance.
  3. One third as large, because the equivalent resistance is three times.
  4. Nine times as large, because power scales with the square of the current.

Explanation

For identical resistors in parallel, the equivalent resistance is one third of a single resistance. Since the battery voltage is unchanged, the total current, V divided by R, becomes three times larger.

Question 41Physics (content domains not enumerated in source)

A wire of resistance R is stretched uniformly so that its length doubles while its volume stays constant. What is its new resistance?

  1. 2R
  2. R/2
  3. 4R Correct answer.
  4. 8R

Explanation

Constant volume means doubling the length halves the cross-sectional area. Resistance is proportional to length divided by area, so it increases by a factor of 2 times 2, giving 4R.

Question 42Physics (content domains not enumerated in source)

A charged particle moves with constant speed in a circle inside a uniform magnetic field. Which quantity is proportional to the radius of its path?

  1. The particle's momentum divided by the product of charge and field strength. Correct answer.
  2. The particle's kinetic energy divided by the field strength.
  3. The product of charge, field strength and speed.
  4. The square root of the particle's charge.

Explanation

The magnetic force provides the centripetal force, so qvB equals mv squared over r, giving r equal to mv divided by qB. The numerator mv is the momentum, so radius is momentum divided by qB.

Question 43Physics (content domains not enumerated in source)

A step-down transformer is used to supply a low-voltage device. Which statement about an ideal transformer is correct?

  1. The secondary current is smaller than the primary current when the voltage is stepped down.
  2. The frequency of the alternating current is halved in the secondary.
  3. The power output exceeds the power input because the voltage falls.
  4. The secondary current is larger than the primary current when the voltage is stepped down. Correct answer.

Explanation

An ideal transformer conserves power, so the product of voltage and current is the same on both sides. If the secondary voltage is lower, the secondary current must be correspondingly higher.

Question 44Physics (content domains not enumerated in source)

An electron in a hydrogen atom falls from the n = 3 level to the n = 2 level. Which statement describes the emitted photon?

  1. Its wavelength is longer than that of a photon from the n = 2 to n = 1 transition.
  2. Its energy equals the sum of the two level energies and lies in the ultraviolet.
  3. Its energy is independent of the energy-level spacing.
  4. Its energy equals the difference between the two energy levels and lies in the visible region. Correct answer.

Explanation

The photon carries exactly the energy difference between the levels, E3 minus E2. This transition is the Balmer alpha line, which falls in the visible part of the spectrum.

Question 45Physics (content domains not enumerated in source)

A nucleus of uranium-238 emits an alpha particle. What are the mass number and atomic number of the daughter nucleus?

  1. Mass number 238, atomic number 90
  2. Mass number 234, atomic number 92
  3. Mass number 234, atomic number 90 Correct answer.
  4. Mass number 236, atomic number 92

Explanation

An alpha particle is a helium-4 nucleus, carrying mass number 4 and atomic number 2. Subtracting these from uranium-238 gives mass number 234 and atomic number 90, which is thorium.

Question 46Physics (content domains not enumerated in source)

A star's spectrum shows a hydrogen absorption line at a wavelength longer than its laboratory value. What can be concluded about the star's motion?

  1. The star is moving away from the observer, producing a redshift. Correct answer.
  2. The star is moving toward the observer, producing a blueshift.
  3. The star's temperature is lower, which shifts all lines equally.
  4. The star is stationary, and the shift arises from its rotation alone.

Explanation

A longer observed wavelength is a redshift, which for galactic and stellar motion indicates recession along the line of sight. The fractional shift gives the radial velocity through the Doppler relation.

Question 47Physics (content domains not enumerated in source)

A satellite in a circular orbit is moved to a higher circular orbit. Which statement about its speed and total energy is correct?

  1. Its orbital speed decreases while its total mechanical energy decreases.
  2. Its orbital speed and total energy both stay the same.
  3. Its orbital speed increases while its total mechanical energy increases.
  4. Its orbital speed decreases while its total mechanical energy increases. Correct answer.

Explanation

For circular orbits, speed is the square root of GM over r, so a larger radius means a smaller speed. The total energy, negative and equal to minus GMm over 2r, becomes less negative as r grows, so it increases.

Question 48Physics (content domains not enumerated in source)

A block of mass m slides down a frictionless track that loops the loop of radius R. What minimum release height above the bottom of the loop allows the block to just maintain contact at the top?

  1. 2R
  2. R
  3. 2.5R Correct answer.
  4. 5R

Explanation

At the top, contact is just maintained when the normal force is zero, so mg equals mv squared over R, giving v squared equal to gR. Energy conservation from the release height h to the top at height 2R then gives h equal to 2R plus R/2, which is 2.5R.

Question 49Physics (content domains not enumerated in source)

Two identical point charges are separated by a distance d. The total electric potential energy of the pair is U. If the separation is halved and one charge is doubled, what is the new potential energy?

  1. U/2
  2. 2U
  3. 4U Correct answer.
  4. U

Explanation

The potential energy of two point charges is k q1 q2 over r. Doubling one charge doubles the energy, and halving the separation doubles it again, so the new energy is 4U.

Question 50Physics (content domains not enumerated in source)

In a photoelectric experiment, the stopping voltage is measured for two frequencies of light on the same metal. A graph of stopping voltage against frequency is plotted. What do the gradient and the intercept on the frequency axis represent?

  1. The gradient is the work function and the intercept is Planck's constant.
  2. The gradient is e/h and the intercept is the work function.
  3. The gradient is h and the intercept is the stopping voltage at zero frequency.
  4. The gradient is h/e and the intercept is the threshold frequency. Correct answer.

Explanation

The photoelectric equation, eV equals hf minus the work function, rearranges to V equal to (h/e)f minus work function over e. The gradient is therefore h/e and the frequency-axis intercept is the threshold frequency.