11. An object at rest is said to possess
- A. potential energy
- B. kinetic energy
- C. chemical energy
- D. electrical energy
Correct Option: Answer is A
Potential energy is the energy that is stored in an object due to its position relative to some zero position
12. According to Newton’s law of cooling, the heat energy lost per unit area of a body depends on the
I. Surface area
II. Nature of the surface
III. Temperature of the surface
IV. Excess temperature over the surroundings
- A. I and II only
- B. II and IV only
- C. I,II and III
- D. I, II and IV
Correct Option: Answer is C
The rate of cooling of liduid according to Newton’s law of cooling depends on:
– Temperature of the liquid
– Temperature of the enclosure
– The area of the exposed surface
– The nature and extent of the surface of the containing vessel
13.
The graph of density against temperature for water is correctly illustrated by
- A. I
- B. II
- C. III
- D. IV
Correct Option: Answer is C
14. A football is kicked at an angle of 45° to the horizontal over a defense line up with a velocity of 15\(ms^{-1}\). Calculate the magnitudeof horizontal velocity of the ball at its highest point [Neglect friction, g = 10\(ms^{-2}\)].
- A. 0.0\(ms^{-1}\)
- B. 5.6\(ms^{-1}\)
- C. 10.6\(ms^{-1}\)
- D. 15.0\(ms^{-1}\)
Correct Option: Answer is C
The horizontal component of velocity, \(V_{x}\), is unaffected by the acceleration of free fall and remains constant.
\(V_{x} = U_{x} = Ucos\theta\)
= \(15 \times cos45 = 15\times 0.7071\)
\(\approxeq 10.6ms^{-1}\)
15. The ice point on the absolute scale of temperature is
- A. 0K
- B. 32K
- C. 100K
- D. 273K
Correct Option: Answer is A
The absolute zero of the scale of temperature being the ice point of the absolute scale of temperature is 0K, which is -273°C.
16. Which of the following factors does not increase the rate of evaporation of water in a lake?
- A. Increase in the pressure of the atmosphere
- B. Rise in temperature
- C. Increase in the surface area of the lake
- D. Increase in the speed of the wind
Correct Option: Answer is A
The rate of evaporation is increased by the lowering of atmospheric pressure and not its increase. Every other factor stands, for the increase of evaporation process.
17. The bob of a simple pendulum takes 8.0s to complete 10 oscillations. Determine the frequency of oscillation of the bob.
- A. 0.125Hz
- B. 1.25Hz
- C. 7.50Hz
- D. 8.00Hz
Correct Option: Answer is C
10 complete oscillations = 8.0s
1 complete oscillation (period) = \(\frac{8}{10}\)s
Frequency = \(\frac{1}{period}\) = \(\frac{1}{0.8} = 1.25Hz\)
18. The diagram above illustrates the mercury-in-glass thermometer used for determining the temperature of a room. Use the data on it to determine the room temperature.
- A. 3.3°C
- B. 7.0°C
- C. 13°C
- D. 30.0°C
Correct Option: Answer is D
Let the room temperature be X.
We have, \(\frac{3-0}{10-0} = \frac{X-0}{100-0}\)
\(\frac{3}{10} = \frac{X}{100}\)
\(X = \frac{3 \times 100}{10}\)
= 30°C
19. Frequency is measured in
- A. meter per second
- B. seconds
- C. hertz
- D. farad
Correct Option: Answer is C
The unit of frequency is hertz, abbreviated Hz.
20. Which of the following electromagnetic waves is most energetic?
- A. Radio waves
- B. X-ray
- C. Gamma rays
- D. Ultra-violet rays
Correct Option: Answer is C
The gamma rays have the shortest wavelength and therefore, impart the highest photon energy.