The breaking stress of a wire depends upon
length of the wire
material of the wire
radius of the wire
shape of the cross-section
The density of a substance at 0°C is 10 g/cc and at 100° C, its density is 9.7 g/cc. The coefficient of linear expansion of the substance is
10-4
102
10-3
102
According to Wein's displacement law
λT = constant
λ/T = constant
λ ∝ ( 1/ T2 )
both (b) and (c)
A black body is at a temperature 300 K. It emits energy at a rate, which is proportional to
300
(300)3
(300)2
(300)4
The latent heat of vapourisation of water is 2240. If the work done in the process of vapourisation of 1 g is 168 J, then increase in internal energy is
2408 J
2072 J
2240 J
1904 J
B.
2072 J
Latent heat of vapourisation of water ( L ) = 2240 J
Mass of water (m) = 1 g
Work done (dW ) = 168 J
From first law of thermodynamics, heat supplied in vapourisation
(dQ) = mL
= dU + dW
1 × 2240 = dU + 168
( where dU = increase in internal energy )
The velocities of sound at the same temperature in two monoatomic gases of densities ρ1 and ρ2 and ν1 and ν2 respectively. If ρ1 / ρ2 = 4, then the value of ν1/ ν2 is
1/4
2
1/2
4
The property utilized in the manufacture of lead shots is
specific weight of liquid lead
compressibility of liquid lead
specific gravity of liquid lead
surface tension of liquid lead
Assertion: Thin films such a soap bubble or a thin layer of oil on water show beautiful colours when illuminated by white light.
Reason: It happens due to the interference of light reflected from upper surface of the thin film.
If both the assertion and reason are true and reason is a correct explanation of assertion.
If both assertion and reason are true but assertion is not a correct explanation of the assertion.
If both the assertion is true but the reason is false.
If both assertion and reason are false.