Physics General Knowledge Questions and Answers – Section 2

Q1. Magnitude of binding energy of satellite is E and kinetic energy is K .The ratio E/K is
A. 1
B. 1/2
C. 2/1
D. 1/4

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Answer: (A) 1

Q2. A heat engine absorbs 360J of energy by heat and performs 25J of work in each cycle. The energy expelled to the cold reservoir in each cycle is
A. 360J
B. 385J
C. 335J
D. 14.4J

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Answer: (C) 335J

Q3. An incompressible non viscous fluid flows steadily through a cylindrical pipe which has radius 2R at point A and radius R at point B farther along the flow direction. If the velocity of the fluid at point A is V, its velocity at the point B will be
A. 2V
B. V
C. V/2
D. 4V

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Answer: (D) 4V

Q4. There are two waves having wavelengths 100cm and 101cm and same velocity 303m/s. The beat frequency is
A. 3Hz
B. 2Hz
C. 4Hz
D. 1Hz

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Answer: (A)3Hz

Q5. Laser light has following property
A. laser light is white light
B. laser light is highly coherent
C. laser light always lies in X-rays region
D. laser light does not have directionality property

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Answer: (B) laser light is highly coherent

Q6. A battery of constant voltage is available. How to adjust a system of three identical capacitors to get high electrostatic energy with the given battery
A. Two parallel and one in series
B. Three in series
C. Three in parallel
D. Whatever may be combination, it will always have same electrostatic energy

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Answer: (C) Three in parallel

Q7. The frequencies of X rays, Gamma rays and visible light waves rays are a, b and c respectively, then
A. a > b > c
B. a > b, b < c
C. a < b, b > c
D. a < b, b < c

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Answer: (C) a < b, b > c

Q8. What is the approximate percentage error in the measurement of time period of a simple pendulum if maximum errors in the measurement of length l and gravitational acceleration g are 3% and 7% respectively ?
A. 2 %
B. 3 %
C. 5 %
D. 10 %

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Answer: (C) 5%

Q9. Two persons A and B start from the same location and walked around a square in opposite directions with constant speeds. The square has side 60m. Speeds of A and B are 4m/s and 2m/s respectively. When will they meet first time?
A. 10 sec
B. 20 sec
C. 30 sec
D. 40 sec

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Answer: (D) 40 sec – 4t+2t = 4(60) => t = 40

Q10. A string fixed at both ends has a standing wave mode for which the distances between adjacent nodes is 18cm. For the next consecutive standing wave mode distances between adjacent nodes is 16cm. The minimum possible length of the string is
A. 288 cm
B. 72 cm
C. 144 cm
D. 204 cm

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Answer: (C) 144 cm
n (18) = l where length of string is l (n+1)(16) = l Gives n=8 and l=144cm.

Q11. A sound wave is generated by the howl of a wolf in the night. How would we describe the motion of a particular air molecule near the ground, a mile away
from the wolf, on average (i.e. ignoring the random wandering of gas molecules)?
A. It moves up and down in an oscillating fashion
B. It moves away from the wolf at the speed of sound
C. It moves back and forth (oscillating) towards the wolf
D. It moves in the horizontal circle.

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Answer: (C) It moves back and forth (oscillating) towards the wolf Sound wave is longitudinal wave.