Alternating Current — Physics STD 12 Science — Question

'Electrons revolve round the nucleus in well-defined orbits, like planets revolve round the sun' was the brainchild of:

Force of attraction between two point charges Q and -Q separated by d metre is . When these charges are placed on two identical spheres of radius R = 0.3d whose centres are d metre apart, the force of attraction between them is

(a) Greater than

(b) Equal to

(c) Less than

(d) Less than

To reduce the reasonant frequency in an LCR series circuit with a generator:

An AC generator is a device which converts:

Two uncharged bodies on rubbing, get charged due to:

Which of one is correct

(a)

(b)

(c)

(d)

The maximum kinetic energy of the photoelectrons emitted from a surface is dependent on the:

In a diffraction pattern by a wire, on increasing diameter of wire, fringe width

(a) Decreases

(b) Increases

(c) Remains unchanged

(d) Increasing or decreasing will depend on wavelength

Assertion  :  In Young’s experiment, the fringe width for dark fringes is different from that for white fringes.

Reason      : In Young’s double slit experiment the fringes are performed with a source of white light, then only black and bright fringes are observed.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.