Atoms — Physics STD 12 Science — Question

In a moving cell galvanometer, we use a radial magnetic field so that the galvanometer scale is:

To use a transistor as an amplifier, emitter-base junction is kept in ...X... and base-collector junction is kept in ...Y... Here, X and Y refer to:

The phenomenon due to which a ray of light .......... from its path while travelling from one optical medium to another optical medium is called refraction.

Choose the correct answer from the alternatives given.
The amplitude of an electromagnetic wave in vaccum is doubled with no other changes made to the wave. As a result of this doubling of the amplitude, which of the following statement is correct?

The coil of dynamo is rotating in a magnetic field. The developed induced e.m.f. changes and the number of magnetic lines of force also changes. Which of the following condition is correct(a) Lines of force minimum but induced e.m.f. is zero(b) Lines of force maximum but induced e.m.f. is zero(c) Lines of force maximum but induced e.m.f. is not zero(d) Lines of force maximum but induced e.m.f. is also maximum

A wavefront presents one, two and three HPZ at points A, B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be (a) 169 : 16  : 256(b) 256 : 16 : 169(c) 256 : 16 : 196(d) 256 : 196 : 16

If a positive charge is shifted from a low-potential region to a high-potential region, the electric potential energy.

A transmitter supplies 9 kW to the aerial when unmodulated. The power radiated when modulated to 40% is (a) 5 kW(b) 9.72 kW(c) 10 kW(d) 12 kW