If temperature of an object is 140°F, then its temperature in centrigrade is

• 105°C

• 32°C

• 140°C

• 60°C

A body of specific heat 0.2 kcal/kg°C is heated through 100°C. The percentage increase in its mass is

• 9 %

• 9.3 x 10^-11 %

• 10 %

• None of these

If E = at + bt², what is the neutral temperature ?

• $- \frac{\mathrm{a}}{2\mathrm{b}}$

• $+ \frac{\mathrm{a}}{2\mathrm{b}}$

• $- \frac{\mathrm{a}}{\mathrm{b}}$

• $+ \frac{\mathrm{a}}{\mathrm{b}}$

204.

An oxide coated filament is useful in vacuum tubes because essentially

• it has high melting point

• it can without and high temperature

• it has good mechanical strength

• it can emit electrons of relatively lower temperature

Which of the following have higher specific change?

• Positron

• Proton

• He

• None of these

Mass of 1 mol of air is 29 x 10^-3 kg. The speed of sound at STP will be nearly

• 332.5 m/s

• 340 m/s

• 320 m/s

• 325 m/s

The length of a steel rod is 5 cm longer than that of a brass rod. If this difference in their lengths is to remain the same at all temperatures, then the length of brass rod will be (coefficient of linear expansion for steel and brass are 12 x 10^-6 /°C and 1.8 × 10^-6 /°C 

• 20 cm

• 15 cm

• 5 cm

• 10 cm

The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively are T₂ and T₁ (T₂ > T₁) . The rate of flow of heat through the slab in steady state is

• $\frac{\mathrm{KA} \left({\mathrm{T}}_1 - {\mathrm{T}}_2\right)}{3\mathrm{x}}$

• $\frac{\mathrm{KA} \left({\mathrm{T}}_2 - {\mathrm{T}}_1\right)}{3\mathrm{x}}$

• $\frac{\mathrm{KA}\hspace{0.17em}\left({\mathrm{T}}_1 - {\mathrm{T}}_2\right)}{2\mathrm{x}}$

• $\frac{\mathrm{KA} \left({\mathrm{T}}_2 - {\mathrm{T}}_1\right)}{2\mathrm{x}}$

One mole of oxygen is heated at a constant pressure from 0°C. What must be the quantity of heat that should be supplied to the gas for the volume to be doubled . (specific heat of oxygen is 0.218 calg^-1K^-1)

• 1700 cal

• 1805 cal

• 1904 cal

• 1612 cal

Two bodies A and B, have thermal emissivities of 0.01 and 0.81 respectively. The outer surface areas of both the bodies are same and emit the same radiated power. The wavelength λ_B , corresponding to the maximum intensity in radiation from B, is shifted from the wavelength λ_A , corresponding to the maximum intensity in radiation from A, by 1 µm. If the temperature of A is 5802 k, then the temperature and wavelength λ_B of body B are

• 1934 K, 3.5 µm

• 1934 K, 1.5 µm

• 1728 K, 32 µm

• 1764 K, 1.8 µm