Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

The binding energy per nucleon of deuterium and helium atom is 1.1 MeV and 7.0 MeV. If two deuterium nuclei fuse to form helium atom, the energy released is(a) 19.2 MeV(b) 23.6 MeV(c) 26.9 MeV(d) 13.9 MeV

When yellow light is incident on a surface, no electrons are emitted while green light can emit. If red light is incident on the surface, then(a) No electrons are emitted(b) Photons are emitted(c) Electrons of higher energy are emitted(d) Electrons of lower energy are emitted

The number of turns and radius of cross-section of the coil of a tangent galvanometer are doubled. The reduction factor K will be (a) K (b) 2K(c) 4K     (d) K/4

A ferromagnetic material is placed in an external magnetic field. The magnetic domains:

1. Increase in size.
2. Decrease in size.
3. May increase or decrease in size.
4. Have no relation with the field.

In a dc motor, induced e.m.f. will be maximum(a) When motor takes maximum speed(b) When motor starts rotating(c) When speed of motor increases(d) When motor is switched off

Energy of electron in excited hydrogen atom is -3.4 eV . According to Bohr's theory, its angular momentum will be :

The quantisation of charge indicates that:

A star is going away from the earth. An observer on the earth will see the wavelength of light coming from the star(a) Decreased(b) Increased(c) Neither decreased nor increased(d) Decreased or increased depending upon the velocity of the star