# Physics 2014 | Study Mode

Question 21
A
Latent heat of vaporization of the liquid
B
Increased vibration of the molecules of the liquid about theit mean position
C
Variation of density of the liquid
D
Expansion of the liquid as it is heated
##### Explanation

Liquids and gases expand when they are heated.The liquid or gas in hot areas is less dense than the liquid or gas in cold areas, so it rises into the cold areas.

Question 22
A
2.0x102Hz
B
4.5x103Hz
C
2.0x103Hz
D
4.5x102Hz
##### Explanation
Wavelength = 15cm = 0.15m

Velocity = 300m/s

V = fx

F = V/Wavelength

F = 300/0.15 Hertz

F = 2 x 103Hz

Question 23
A
528m
B
66m
C
136m
D
264m
##### Explanation
Time for echo both ways = 0.8
Therefore time for echo in 1 way = 0.8/2 = 0.4

Distance = Speed x time

Distance = 340 x 0.4

Distance = 136m

Question 24
A
2.5x102
B
2.5x10-2
C
2.5x10-1
D
2.5x101
##### Explanation
$$\text{Linear Magnification} = \frac{\text{Length of Camera}}{\text{Distance of the Object}}$$

$$\text{Linear Magnification} = \frac{25}{1000}$$

$$\text{Linear Magnification} = 2.5 \times 10^{-2}$$

Question 25
A
2.7m
B
2.0m
C
2.3m
D
2.5m
##### Explanation
$$\frac{1}{U} + \frac{1}{V} = \frac{1}{f}$$

$$\frac{1}{8} + \frac{1}{V} = \frac{1}{2}$$

$$V = \frac{8}{3}$$

$$V = 2.7cm$$

Question 26
A
At infinity
B
Long
C
Short
D
The same

Question 27
A
Infinity
B
The focus
C
D
The near point
##### Explanation

Question 28
A
Remains the same
B
Collapses
C
Collapses and diverges again
D
Diverges

Question 29
A
1C
B
5C
C
4C
D
2C
##### Explanation

Q = CV = 0.1 x 10 = 1C

Question 30
A
Twice the internal resistance of the cell
B
The same as the internal resistance of the cell
C
Greater than the internal resistance of the cell
D
Less than the internal resistance of the cell