Multiple Choice Questions

Transcription

1 Multiple Choice Questions 1. A resistor is connected to a cell, a rheostat, an ammeter and a voltmeter as shown above. Which of the following predictions about the readings of the ammeter (A) and the voltmeter (V) is/are correct, when the sliding contact point of the rheostat moves to the left? voltmeter reading (V) ammeter reading (A) A. increases decreases B. decreases increases C. increases increases D. decreases decreases Page 1 of 6

2 2. The above figure shows the waveform of a sinusoidal current I as a function of time t. If the current I is applied across a 20 Ω resistor, what is the average power dissipated by the resistor? A. 0 W B. 1.6 W C W D. 3.2 W 3. The figure above shows the cross-sections of two parallel long straight wires R and S. The separation between the wires is 4 cm. The current in R is 1A and flows into the paper. It is given that the resultant magnetic field at P is zero, and the distance between P and R is 1 cm. Find the magnitude and direction of the current flowing in wire S. Magnitude of the current flowing in wire S. Direction of the current flowing in wire S. A. 3 A into the paper. B. 4 A into the paper. C. 3 A out of the paper. D. 4 A out of the paper. Page 2 of 6

3 4. A 6 N force and a 1 N force are combined to form a resultant force, F. Which of the following is/are the possible magnitude(s) of F? (1) 4 N (2) 6 N (3) 7 N A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 5. Arrange the normal reaction forces acting on cubes by the planes in ascending order of their magnitude. (1) Cube is at rest on a horizontal plane. (2) Cube is at rest on an 20 inclined plane. (3) Cube is at rest on an 30 inclined plane A. (1) < (2) < (3) B. (2) < (1) < (3) C. (3) < (1) < (2) D. (3) < (2) < (1) Page 3 of 6

4 6. A ball is projected upward from the ground at an angle to the horizontal. The horizontal and vertical components of the initial velocity of the ball are 10 m s 1 and 15 m s 1, respectively. Neglecting the effect of air resistance, what are the horizontal and vertical components of the velocity after 2 s? horizontal vertical A B C D An astronaut above the Earth s surface experiencing a gravitational field strength of 8 N kg 1. What is his distance from the centre of the Earth? Given: The mass of the Earth is kg. The gravitational constant is N m 2 kg -2. A m B m C m D m 8. We feel cooler when touching a metal handrail as compared with touching a wooden handrail on the same day because A. the metal handrail has a lower temperature than the wooden handrail. B. the metal has a lower specific heat capacity than wood. C. the metal has a higher heat conductivity than wood. D. the metal has a higher melting point than wood. Page 4 of 6

5 9. The figure below shows a displacement-distance graph of a wave travelling to the left. Which of the particles P, Q and R is/are moving downward at the instant shown? A. Particle Q only B. Particle R only C. Particles P and Q D. Particles P and R 10. A series of plane waves travel from medium I into medium II. The speed of the wave is found to have reduced when it travels from medium I to medium II. Which of the following figures correctly shows the positions PQ and P Q of a wavefront before and after entering the medium II? A. B. C. D. Page 5 of 6

6 11. A beam of monochromatic light falls at normal incidence on a diffraction grating, and bright fringes of different orders are formed on a screen. The second-order bright fringes are found at angles of 30 o relative to the incident direction. What is the maximum total number of bright fringes formed on the screen? A. 4 B. 5 C. 7 D. 9 Page 6 of 6