IB Physics Higher Level

1. Which quantity has the same units as those for energy stored per unit volume? A. Density B. Force C. Momentum D. Pressure

2. An object of mass 8.0 kg is falling vertically through the air. The drag force acting on the object is 60 N. What is the best estimate of the acceleration of the object? A. Zero B. 2.5 m s–2 C. 7.5 m s–2 D. 10 m s–2

3. A body is held in translational equilibrium by three coplanar forces of magnitude 3 N, 4 N and 5 N. Three statements about these forces are I. all forces are perpendicular to each other II. the forces cannot act in the same direction III. the vector sum of the forces is equal to zero. Which statements are true? A. I and II only B. I and III only C. II and III only D. I, II and III

4. An object of mass 1 kg is thrown downwards from a height of 20 m. The initial speed of the object is 6 m s–1. The object hits the ground at a speed of 20 m s–1. Assume g = 10 m s–2. What is the best estimate of the energy transferred from the object to the air as it falls? A. 6 J B. 18 J C. 182 J D. 200 J

5. A car is driven from rest along a straight horizontal road. The car engine exerts a constant driving force. Friction and air resistance are negligible. How does the power developed by the engine change with the distance travelled? A. Power does not change. B. Power decreases linearly. C. Power increases linearly. D. Power increases non-linearly.

6. An object of mass 2m moving at velocity 3v collides with a stationary object of mass 4m. The objects stick together after the collision. What is the final speed and the change in total kinetic energy immediately after the collision? Final speed Change in total kinetic energy A. v 3 mv 2 B. v 6 mv 2 C. 2v 3 mv 2 D. 2v 6 mv 2

7. What is not an assumption of the kinetic model of an ideal gas? A. Attractive forces between molecules are negligible. B. Collision duration is negligible compared with time between collisions. C. Molecules suffer negligible momentum change during wall collisions. D. Molecular volume is negligible compared with gas volume.

Turn over 8. A substance in the gas state has a density about 1000 times less than when it is in the liquid state. The diameter of a molecule is d. What is the best estimate of the average distance between molecules in the gas state? A. d B. 10d C. 100d D. 1000d

9. Two containers X and Y are maintained at the same temperature. X has volume 4 m3 and Y has volume 6 m3. They both hold an ideal gas. The pressure in X is 100 Pa and the pressure in Y is 50 Pa. The containers are then joined by a tube of negligible volume. What is the final pressure in the containers? A. 70 Pa B. 75 Pa C. 80 Pa D. 150 Pa

10. An object moves with simple harmonic motion. The acceleration of the object is A. constant. B. always directed away from the centre of the oscillation. C. a maximum at the centre of the oscillation. D. a maximum at the extremes of the oscillation.

11. A travelling wave has a frequency of 500 Hz. The closest distance between two points on the wave that have a phase difference of 60 rad 3 π       is 0.050 m. What is the speed of the wave? A. 25 m s–1 B. 75 m s–1 C. 150 m s–1 D. 300 m s–1

12. Wavefronts travel from air to medium Q as shown. air Q 45° 30° Q 45° 30° What is the refractive index of Q? A. sin sin 30 45 o o B. sin sin 45 30 o o C. sin sin 45 60 o o D. sin sin 60 45 o o

Turn over 13. The air in a pipe, open at both ends, vibrates in the second harmonic mode. Q P What is the phase difference between the motion of a particle at P and the motion of a particle at Q? A. 0 B. 2 π C. π D. 2π

14. A metal wire has n free charge carriers per unit volume. The charge on the carrier is q. What additional quantity is needed to determine the current per unit area in the wire? A. Cross-sectional area of the wire B. Drift speed of charge carriers C. Potential difference across the wire D. Resistivity of the metal

15. A cell of electromotive force (emf) E and zero internal resistance is in the circuit shown. R R W Z X Y I3 I1 I2 R R 2R U What is correct for loop WXYUW? A. E = 3I1R – I3R B. E = I3R – I2R C. E = I3R D. E = 2I2R – I3R

16. What is the relationship between the resistivity ρ of a uniform wire, the radius r of the wire and the length l of the wire when its resistance is constant? A. ρ ∝ r 2l B. ρ ∝ rl 2 C. ρ ∝ 2 r l D. ρ ∝ 2 r l

17. A power station generates 250 kW of power at a potential difference of 25 kV. The energy is transmitted through cables of total resistance 4.0 Ω. What is the power loss in the cables? A. 0.04 kW B. 0.4 kW C. 4 kW D. 40 kW

Turn over 18. An electrical power supply has an internal resistance. It supplies a direct current I to an external circuit for a time t. What is the electromotive force (emf) of the power supply? A. total energy transferred to the whole circuit I ×t B. total power transferred to the whole circuit I ×t C. total energy transferred to the external circuit I ×t D. total power transferred to the external circuit I ×t

19. A current in a wire lies between the poles of a magnet. What is the direction of the electromagnetic force on the wire? A. B. C. D. N S current

20. Mass M is attached to one end of a string. The string is passed through a hollow tube and mass m is attached to the other end. Friction between the tube and string is negligible. r m M Mass m travels at constant speed v in a horizontal circle of radius r. What is mass M? A. mv r 2 B. mv 2rg C. mgv r 2 D. mv gr 2