According to Huygens principle, the amplitude of secondary wavelets is

The radius of the $$\mathrm{n}^{\text {th }}$$ orbit in Bohr model of hydrogen atom is proportional

Assertion (A) : The resistance of an intrinsic semiconductor decreases with increase in its temperature.

Reason (R) : The number of conduction electrons as well as hole increase in an intrinsic semiconductor with rise in its temperature.

Assertion (A) : The equivalent resistance between points A and B in the given network is 2R.

Reason (R) : All the resistors are connected in parallel