Nuclei — Physics STD 12 Science — Question

Potential gradient is defined as

(a) Fall of potential per unit length of the wire

(b) Fall of potential per unit area of the wire

(b) Fall of potential per unit area of the wire

(d) Potential at any one end of the wire

If the value of C in a series RLC circuit is decreased, the resonant frequency.

The number of turns in the primary coil of a transformer is 200 and the number of turns in the secondary coil is 10. If 240 volt AC is applied to the primary, the output from the secondary will be

(a) 48 V

(b) 24 V

(c) 12 V

(d) 6 V

The magnitude of electric field intensity E is such that, an electron placed in it would experience an electrical force equal to its weight is given by

(a) mge

(b)

(c)

(d)

A hole diffuses from the p-side to the n-side in a p-n junction. This means that.

1. A bond ia broken on the n-side and the electron freed from the bond jumps to the conduction band.
2. A conduction electron on the p-side jumps to a broken bond to complete it.
3. A bond is broken on the n-side and the electron freed from the bond jumps to a broken bond on the p-side to complete it.
4. A bond is broken on the p-side and the electron freed from the bond jumps to a broken bond on the n-side to complete it.

​​​​50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be:

1. 0%
2. < 50%
3. 50%
4. > 50%

A radioactive substance has a half life of 60 minutes. After 3 hours, the fraction of atom that have decayed would be

(a)12.5%

(b) 87.5%

(c) 8.5%

(d) 25.1%

The properties of a surface are different from those of the bulk liquid because the surface molecules:

1. Are smaller than other molecules.
2. Acquire charge due to collision from air molecules.
3. Find different type of molecules in their range of influence.
4. Feel a net force in one direction.

In non-resonant circuit, what will be the nature of the circuit for frequencies higher than the resonant frequency?

Two slits are separated by a distance of 0.5 mm and illuminated with light of λ = 6000 Å. If the screen is placed 2.5 m from the slits. The distance of the third bright image from the centre will be

(a) 1.5 mm

(b) 3 mm

(c) 6 mm

(d) 9 mm