# Physics 2018 | Study Mode

Question 11
A
I and II only
B
II and IV only
C
I,II and III
D
I, II and IV
##### Explanation

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

Question 12
A
I
B
II
C
III
D
IV
##### Explanation

Question 13
A
0.0$$ms^{-1}$$
B
5.6$$ms^{-1}$$
C
10.6$$ms^{-1}$$
D
15.0$$ms^{-1}$$
##### Explanation

The horizontal component of velocity, $$V_{x}$$, is unaffected by the acceleration of free fall and remains constant.

$$V_{x} = U_{x} = Ucos\theta$$

= $$15 \times cos45 = 15\times 0.7071$$

$$\approxeq 10.6ms^{-1}$$

Question 14
A
0K
B
32K
C
100K
D
273K
##### Explanation

The absolute zero of the scale of temperature being the ice point of the absolute scale of temperature is 0K, which is -273C.

Question 15
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
##### Explanation

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.

Question 16
A
0.125Hz
B
1.25Hz
C
7.50Hz
D
8.00Hz
##### Explanation

10 complete oscillations = 8.0s

1 complete oscillation (period) = $$\frac{8}{10}$$s

Frequency = $$\frac{1}{period}$$ = $$\frac{1}{0.8} = 1.25Hz$$

Question 17
A
I and III only
B
I and II only
C
II and III only
D
I, II and III
##### Explanation

In SHM, the body must have acceleration in a direction opposite to the displacement and the acceleration must be directly proportional to displacement. Also, the acceleration must be directed towards its mean position. This is not the case with a football on the pitch.

Question 18
A
3.3C
B
7.0C
C
13C
D
30.0C
##### Explanation

Let the room temperature be X.

We have, $$\frac{3-0}{10-0} = \frac{X-0}{100-0}$$

$$\frac{3}{10} = \frac{X}{100}$$

$$X = \frac{3 \times 100}{10}$$

= 30C

Question 19
A
meter per second
B
seconds
C
hertz
D
##### Explanation

The unit of frequency is hertz, abbreviated Hz.

Question 20
A
B
X-ray
C
Gamma rays
D
Ultra-violet rays
##### Explanation

The gamma rays have the shortest wavelength and therefore, impart the highest photon energy.

Try this quiz in in E-test/CBT Mode
switch to

Question Map