# 30 Physics Questions for Examination and Answers

1. A boat travels due east at a speed of 40 ms-1 across a river flowing due south at 30ms-1. What is the resultant speed of the boat?

A. 1.3 ms-1  B. 10.0 ms-1 C. 50.0 ms-1 D. 70.0 ms-1

2. An objected is projected with a velocity 80 ms-1 at an angle of 30Â° to the horizontal. The maximum height reached is?

A. 20 m  B. 80 m  C. 160 m  D. 320 m

3. A motor vehicle is brought to a rest from a speed of 15 ms-1 in 20 seconds. Calculate the retardation.

A. 0.75 ms-2    B. 1.33 m-2    C. 5.00 ms-2      D. 7.50 ms-2

4. A stone thrown vertically upwards returns to the ground. Which of the following figures represents the velocity-time graph?

5. Calculate the magnitude of the force required to just move a 20kg object along a horizontal surface if the coefficient of friction is 0.2 [g = 10ms-2]
A. 400.0N B. 40.0N C. 4.0N  D. 0.4N
6. The equation of a transverse wave travelling along a string is given by y = 0.3 sin (0.5x-50t) where y and x are in cm and t seconds. Find the maximum displacement of the particles from the equilibrium position.
A. 50.0 cm B. 2.5 cm  C. 0.5 cm   D. 0.3 cm
7. Which of the following is the dimension of pressure?
A. ML-1         B. MLT-2         C. ML2T-3        D. ML-3
8. The length of a displaced pendulum bob which passes its lowest point twice every second is
A. 0.25 m       B. 0.45 m          C. 0.58          D.1.00 m
9. Which of the following statements are TRUE about frictional force?
I. it is always a disadvantage
II. It is sometimes a disadvantage
III. It is always exists where there is a relative motion of two bodies that are in contact
IV. It is sometimes very useful.
A. I and III only B. I and IV only
C. II and III only D. II and IV only
10. Which of the following is the exclusive property of a transverse wave?                                                                                           A. Diffraction                     B. Refraction   C. Compression                                D. Polarization
11. The wavelength of signals from a radio transmitter is 1500m and the frequency is 200 kHz. What is the wave length for a transmitter operating at 1000 kHz?
A. 7 500m       B. 300 m      C. 7.5 m        D. 1.5 m
12. The difference between sound waves and light waves is that sound waves
A. are transverse while light waves are longitudinal
B. require a medium to travel while light waves do not
C. can be diffracted but light waves cannot
D. cannot be reflected but light waves can
13. At what respective values of x, y and z would the unit of force, the Newton, be dimensionally equivalent to MXLYTZ?
A. -1, 1, 2      B. 1, 1, -2      C. 1, -1, 2        D. -1, 1, -2
14. The distance Xm travelled by a particle in time t seconds is described by the equation x = 10 + 12t2. Find the average speed of the particle between the interval t = 2s and t = 5s.
A. 60 ms-1      B. 72 ms-1         C. 84 ms-1            D. 108 ms-1
15. A 5kg block is released from rest on a smooth plane at an angle of 30Â° to the horizontal. What is the acceleration down the plane?
A. 5.0 ms-2  B. 5.8-2  C. 8.7 ms-2  D. 25.0 ms-2
16. Two bodies X and Y are projected on the same horizontal plane, with the same initial speed but at angle 30Â° and 60Â° respectively to the horizontal. Neglecting air resistance, the ration of the range of X to that of Y is
A. 1 : 1       B. 1 : 2        C.âˆš3 : 1 D. âˆš1 : 3
17. Ripples on water and light waves are similar because both
A. have the same frequency                                        B. can be refracted and diffracted
C. are longitudinal waves     D. have the same velocity
18. In electromagnetism, induced emf is dependent of one of the following                            A. magnetic flux density  B. direction of magnetic field     C. length of coil    D. material of the coil
19. Find the force on a coil of length 5m carrying a 5A current; perpendicular to a magnetic field of flux 30Wb covering an area of 5mÂ²                        A. 150N  B. 75N  C. 15N  D. 75N
20. One of the following is not a tangible loss in a transformer                                                                  A. Eddy current loss  B. hysterisis loss  C. heat loss     D. none of the above
21. Which of the following materials would likely utilize a permanent magnet
A. ac generator           B. DC dynamo C. telephone earpiece    D. simple bar magnet
22. To convert an AC generator to a DC generator,
A. you must replace the slip ring with split ring      B. you must replace the split ring with slip ring    C. A or B above  D. none of the above
23. Find the ratio of secondary to primary turns in a transformer that delivers 10V from a 2V input
A. 2:5  B. 5:1  C. 1:5  D. 1:1
24. Given that the energy stored in a 0.2H inductor carrying is 0.4J, calculate the current
A. 1.0A  B. 3.2A   C. 4A   D. 2A
25. In Fleming’s right hand rule, the direction of the middle finger indicates,
A. direction of magnetic field                                      B. direction of induced current                                  C. direction of force on the conductor                      D. direction of motion in the conductor
26. Calculate the resonant frequency in a circuit containing a 0.4H inductor and a 10F capacitor
A. 0.06Hz  B. 0.07Hz   C. 0.08Hz    D. 0.09Hz
27. Which of the following methods of demagnetization cannot be used for demagnetization
A. Hammering
B. heating
C. solenoid method
D. none of the above
28. A car of mass 320kg moving at 12m/s suddenly observes a dog 110m ahead. If the driver applies a brake producing a retarding
A. 14.4m away from the dog after hitting it            B. 87.6m away from the dog before hitting it          C. 14.4m away from the dog before hitting it          D. 85.6m away from the dog before hitting it
29. A car of mass 3kg, is moving at a velocity of 10m/s for 2s. The force on the car is                           A. 15N  B. 30N  C. -30N  D.0N
30. The sudden sensation received by a body as a result of the sudden application of a force is    A. Impulse
B. Acceleration
C. Velocity
D. Pressure
1. C
2. B
3. A
4. B
5. B
6. D
7. NA
8. D
9. C
10.D
11. B
12. B
13. B
14. C
15. C
16. A
17. B
18. D
19. NA
20. D
21. A
22. B
23. B
24. NA
25. B
26. C
27. D
28. D
29 D
30. A