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Let 'p' and 'E' denote the linear momentum and energy of emitted photon respectively. If the wavelength of incident radiation is increased ___ .
(a) both p and E increase
(b) p increases and E decreases
(c) p decreases and E increases
(d) both p and E decrease.
Concept: Qualitative Ideas of Black Body Radiation
Show that R.M.S. velocity of gas molecules is directly proportional to square root of its absolute temperature.
Concept: Assumptions of Kinetic Theory of Gases
A circular coil of 250 turns and diameter 18 cm carries a current of 12A. What is the magnitude of magnetic moment associated with the coil?
Concept: Moving Coil Galvanometer
The wavelength range of thermal radiation is
(A) from 4000 Å to 7000 Å
(B) from 7700 Å to 4 x 106 Å
(C) from 106 Å to 108 Å
(D) from 4 x 10-12 Å to 4 x 108 Å
Concept: Qualitative Ideas of Black Body Radiation
A metal ball cools from 64 °C to 50 °C in 10 minutes and to 42 °C in next 10 minutes. The ratio of rates of fall of temperature during the two intervals is _______.
Concept: Temperature and Heat
The susceptibility of magnesium at 300 K is 2.4 x 10-5. At what temperature will the susceptibility increase to 3.6 x 10-5?
Concept: Temperature and Heat
When electron in hydrogen atom jumps from second orbit to first orbit, the wavelength of radiation emitted is λ. When electron jumps from third orbit to first orbit, the wavelength of emitted radiation would be _______.
(A)`27/32lambda`
(B)`32/27lambda`
(C)`2/3lambda`
(D)`3/2lambda`
Concept: Qualitative Ideas of Black Body Radiation
An ideal voltmeter has _______.
(A) low resistance
(b) high resistance
(C) infinite resistance
(D) zero resistance
Concept: Moving Coil Galvanometer
Find the wavelength at which a black body radiates maximum energy, if its temperature is 427°C.
(Wein’s constant b = 2.898 × 10-3 mK)
(A) 0.0414 × 10-6m
(B) 4.14 × 10-6m
(C) 41.4 × 10-6m
(D) 414 × 10-6m
Concept: Qualitative Ideas of Black Body Radiation
Prove that root mean square velocity of gas molecule is directly proportional to the square root of its absolute temperature.
Concept: Assumptions of Kinetic Theory of Gases
A body cools at the rate of 0.5°C / minute when it is 25° C above the surroundings. Calculate the rate of cooling when it is 15°C above the same surroundings.
Concept: Derivation of Boyle’s Law
Explain how moving coil galvanometer is converted into a voltmeter. Derive the necessary formula.
Concept: Moving Coil Galvanometer
A rectangular coil of a moving coil galvanometer contains 100 turns, each having area
15 cm2. It is suspended in the radial magnetic field 0.03 T. The twist constant of suspension
fibre is 15 x 10-10 N-m/degree. Calculate the sensitivity of the moving coil galvanometer.
Concept: Moving Coil Galvanometer
At what temperature will average kinetic energy of gas be exactly half of its value at N.T.P.?
Concept: Assumptions of Kinetic Theory of Gases
1000 tiny mercury droplets coalesce to form a bigger drop. In this process, temperature of the drop _______ .
(A) increases
(B) may increase or decrease
(C) decreases
(D) does not change
Concept: Temperature and Heat
If the total kinetic energy per unit volume of gas enclosed in a container is E, the pressure exerted by the gas is
(A) E
(B) 3/2 E
(C) `sqrt3E`
(D) 2/3E
Concept: Assumptions of Kinetic Theory of Gases
Two gases exert pressure in the ratio 3: 2 and their densities are in the ratio 2: 3, then the ratio of their R.M.S. velocities is ...........
Concept: Derivation for Pressure of a Gas
A body cools from 62°C to 54°C in 10 minutes and to 48°C in the next 10 minutes. Find the temperature of the surroundings.
Concept: Temperature and Heat
The fraction of the total current passing through the galvanometer is ............ .
a) `S/(S+G)`
b) `G/(S+G)`
c) `(S+G)/G`
d) `(S+G)/S`
Concept: Moving Coil Galvanometer
The susceptibility of magnesium at 300K is 1.2 x 10-5. At what temperature will the susceptibility increase to 1.8 X 10-5?
Concept: Temperature and Heat
