Nuclei — Physics STD 12 Science — Question

A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is(a) 64.7 V/m(b) 57.8 V/m(c) 56.72 V/m(d) 54.77 V/m

The empirical atom model was given by:

Ratio between intensities of magnetic fields due to points situated on axial and non-axial positions of a small magnet at distance from it is:

Speed of electromagnetic waves in vacuum is:

A metal block is exposed to beams of X-ray of different wavelength. X-rays of which wavelength penetrate most?

A vertical straight conductor carries a current vertically upwards. A point P lies to the east of it at a small distance and another point Q lies to the west at the same distance the magnetic field at P is:

According to corpuscular theory of light, the different colours of light are due to(a) Different electromagnetic waves(b) Different force of attraction among the corpuscles(c) Different size of the corpuscles(d) None of the above

A conducting wire connects two charged conducting spheres such that they attain equilibrium with respect to each other. The distance of separation between the two spheres is very large as compared to either of their radii.
The ratio of the magnitudes of the electric fields at the surfaces of the two spheres is

Which of these is unipolar transistor(a) Point contact transistor(b) Field effect transistor(c) PNP transistor(d) None of these