## Physics Study Mode

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Question 781
A
take place at any temperature
B
are surface phenomena
C
involve change of state
D
take place at a definite pressure
Explanation.

No official Explanation yet!

Question 782
A
expands uniformly
B
is opaque
C
is several times denser than water
D
is a good conductor of heat
Explanation.

No official Explanation yet!

Question 783
A
high coefficient of expansion
B
good conduction of heat
C
low specific heat capacity
D
Explanation.

No official Explanation yet!

Question 784
A
150cm3
B
273cm3
C
327cm3
D
600cm3
Explanation.
$$\frac{V_1}{T_1}$$ = $$\frac{V_2}{T_2}$$

$$\frac{300}{27 + 273}$$ = $$\frac{V_2}{54 + 273}$$

V2 = 327cm3

Question 785
A
1 : 4
B
4 : 1
C
1 : 1
D
2 : 1
Explanation.
$$\theta$$p = 2$$\theta$$q

mq = 2mp

Cp X mp X $$\theta$$p = Cq x mq x $$\theta$$q

$$\frac {C_pm_q\theta q}{C_qm_p \theta q}$$ = $$\frac {\theta q \times 2mp}{2 \theta qmp}$$

$$\frac {C_p}{Cq}$$ = $$\frac {2}{2}$$

Question 786
A
sound travels faster in air at 20oC than at 30o
B
the frequency of a given sound wave changes when it crosses the boundary seperating two media
C
the wavelength of a given sound wave in air decreases as the temperature increases
D
sound waves cannot be reflected
Explanation.

No official Explanation yet!

Question 787
A
8.0cm
B
16.0cm
C
24.0cm
D
32.0cm
Explanation.
F = 12cm, V = 3u

F = $$\frac{uv}{u + v}$$

12 = $$\frac{u\times 3u}{u + 3v}$$

u = 16cm, and v = 48cm

therefore, distance between u and v

v = 48 - 16 = 32cm

Question 788
A
Gamma rays, infra-red rays, x-rays, radiowaves
B
Gamma rays, x-rays, infra-red ray, radiowaves
C
Radiowaves, x-rays, gamma ray, infra-red rays
D
Infra-red rays, radiowaves, x-rays, gamma rays
Explanation.

No official Explanation yet!

Question 789
A
sin-1$$\frac{1}{2}$$
B
sin-1$$\frac{2}{3}$$
C
sin-1$$\frac{3}{4}$$
D
sin-1$$\frac{8}{9}$$
Explanation.
sin ic $$\frac{1}{n}$$ = $$\frac{1}{1 - 5}$$

i = sin-1$$\frac{1}{1 - 5}$$

= sin-1$$\frac{10}{15}$$

= sin-1$$\frac{2}{3}$$

Question 790
A
5.3cm
B
3.2cm
C
2.7cm
D
1.6cm
Explanation.
v = 4u, if u = 2cm, v = 8cm

F = $$\frac{uv}{u + v}$$

= $$\frac{2 \times 8}{2 + 8}$$

= 1.6cm

r = 2F

= 2 x 1.6

= 3.2cm

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