E-JUST s Sample Entrance Exam Faculty of Engineering

Transcription

1 E-JUST s Sample Entrance Exam Faculty of Engineering PHYSICS Time: 1 hr Choose the right answer: 1. Three equal resistors connected in series across a source e.m.f. together dissipate 10 watt. If the same resistors are connected in parallel across the same e.m.f. the power dissipated will be A. 10 Watt B. 30 Watt C. 10/3 Watt D. 90 Watt E. 120 Watt 2. Look at the figure. The equivalent resistance between A and D is A. 15 B. 5 C. 10 D. 25

2 3. If a beam of photon incidents on a surface, every reflected photon has a change in the momentum. The force that a 1-watt photon beam affects on a wall surface is A x 10-8 N B. 6.7 x 10-8 N C x 10-8 N D. 3.3 x 10-8 N 4. Calculate the wavelength of a mass of 140 g moving at 40 m/s, and the wavelength of an electron moving at the same velocity A. λ = 1.18 x m, λe = 1.8 x 10-5 m B. λ = 1.8 x 10-5 cm, λe = 1.8 x cm C. λ = 1.8 x 10-5 nm, λe = 1.8 x 10-5 nm D. λ = 1.18 x mm, λe = 1.8 x mm 5. Say you want to ride your bike to E-JUST. If E-JUST is 48 km from your house, and you can average 16 km/hr on your bike, what time do you have to leave to arrive at noon? A. 7 AM B. 8 AM C. 9 AM D. 10 AM E. 11 AM 6. The position of an object moving along the x-axis is defined as, x = 20t 2, where t is the time measured in seconds and position is expressed in meters. Calculate the average velocity of the object over the time interval from 3s to 4s. A. 140 ms -1 B ms -1

3 C. 14 ms -1 D. 144 ms -1 E. 148 ms A train A is moving on a straight track (or railway line) from North to South with a speed of 60 Km.h -1. Another train B is moving from South to North with a speed of 70 Km.h -1. What is the velocity of B relative to the train A? A. 130 Km.h -1 B. 10 Km.h -1 C. 65 Km.h -1 D. 120 Km.h The main difference(s) between a radio wave and a light wave is(are) its A. speed. B. wavelength. C. frequency. D. both a and b E. both b and c 9. Which of these electromagnetic waves has the shortest wavelength? A. radio waves B. infrared waves C. X rays D. ultraviolet waves E. light waves

4 See the figure below to answer question The effect in which white light separates into different colors is called A. magnification B. refraction C. reflection A. dispersion E. All of these 11. Materials generally become warmer when light is A. absorbed by them. B. reflected by them. C. transmitted by them. D. all of these. E. none of these 12. Which quantity has the greatest influence on the amount of kinetic energy that a large truck has while moving down the highway? A. mass B. weight C. velocity D. size E. potential energy

5 13. Most of the waves in the electromagnetic spectrum are A. Blue light B. Green light C. Red light D. Black E. Invisible 14. The face that light travels at 300,000 km/s is a consequence of A. Electromagnetic wave propagation B. Electromagnetics field induction C. Energy conservation D. Maxwell s laws 15. If an electron vibrates up and down 1000 times each second, it generates an electromagnetic wave having: A. Speed of 1000 m/s B. Frequency of 1000 Hz C. Period of 1000 s D. Wavelength of 1000 km E. Wavelength of 1000 m 16. When light reflects from a surface, there is a change in its A. Frequency B. Speed C. Wavelength D. All of these

6 17. Principle of laser is A. spontaneous absorption B. stimulated emission C. induced emission D. both b and c 18. If water falls from a dam into a turbine wheel 19.6 m below. Then velocity of water at turbine is A. 9.8 m/s B m/s C m/s D. 98 m/s 19. The mass of a photon A. is 0 B. is the same as that of an electron C. depends on its frequency D. depends on its energy 20. From the figure below, a coil with inductance 1.00 mh is connected to a 60.0-kHz ac power source of 110 V, What is the current in the circuit?

7 A A B A C A D. 3.96