**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.