A longitudinal wave is represented by . The maximum particle velocity will be four times the wave velocity if
A block of ice at temperature -20°C is slowly heated and converted to steam at 100°C. Which of the following diagram is most appropriate ?
A.
The ice at -20° C converts to ice at 0° C, thus having an increase in temperature. On further heating, ice at 0°C is converted into water at 0°C, thus the temperature remaining constant, a change of phase occurs. Water at 0°C when heated changes to water at 100°C, thus resulting in an increase of temperature. Water at 100°C changes to steam at 100°C, thus resulting in a change of phase. Hence, Fig. (A) is the correct answer.
Two black bodies at temperatures 327°C and 427°C are kept in an evacuated chamber at 27°C. The ratio of their rates of loss of heat are
A point charge +q is placed at the centre of a cube of side L. The electric flux emerging from the cube is
zero
In the figure below, the capacitance of each capacitor is 3 µF. The effective capacitance between A and B is
3 µF
6 µF
5 µF
A wire of resistance R is elongated n-fold to make a new uniform wire. The resistance of new wire
nR
n2R
2nR
2n2R
The ratio of magnetic field and magnetic moment at the centre of a current carrying circular loop is x. When both the current and radius is doubled the ratio will be
x/8
x/4
x/2
2x
The current through a coil of self-inductance L = 2mH is given by i = t2e-t at time t. How long it will take to make the emf zero ?
1 s
2 s
3 s
4 s
The magnetic flux through a loop of resistance 10 Ω is given by (=5t2 − 4t+ 1 Wb). How much current is induced in the loop after 0.2 s ?
0.4 A
0.2 A
0.04 A
0.02 A