The velocity of sound in air at NTP is 330 m/s. What will be its value when temperature is doubled and pressure is halved?

 

1.  330 m/s

2.  165 m/s

3.  330 m/s

4.  330/ m/s

 

Doppler’s effect is sound in addition of relative velocity between source and observer or both are moving. Doppler effect in light depend only on the relative velocity of source and observer. The reason of this is

 

If EMF = 4 volt ω = 1000t volt is applied to an L-R circuit of inductance 3 mH and resistance 4Ω, the amplitude of current in the circuit is

 

The X-ray tube s operated at 50 kV. The minimum wavelength produced is

 

The energy gap between conduction band and valence band if of the order of 0.07 eV. It is a/an

 

The earth circles around the sun once a year. The work which would have to be done on the earth to bring it to rest relative to the sun is, (Ignore the rotation of earth about its own axis) given that the mass of the earth = 6×10²⁴ kg and the distance between sun and earth is 1.5×10⁸ km)

 

A longitudinal wave is represented by 
x= x₀ sin2π 
The maximum particle velocity will be four times the wave velocity, if

 

The rate of dissipation of heat by a black body at temperature T is Q. What will be the rate of dissipation of heat by another body at temperature 2 T and emissivity 0.25?

 

1.  16 Q
2.  4 Q
3.  8 Q
4.  4.5 Q

The radius of gyration of a body about an axis at a distance of 6 cm from its centre of mass is 10 cm. Then, its radius of gyration about a parallel axis through its centre of mass will be

 

1.  800 cm
2.  8 cm
3.  0.8 cm
4.  80 cm