Electromagnetic Induction — Physics STD 12 Science — Question

The north and south poles of two identical magnets approach a coil, containing a condenser, with equal speeds from opposite sides. Then

(a) Plate 1 will be negative and plate 2 positive

(b) Plate 1 will be positive and plate 2 negative

(c) Both the plates will be positive

(d) Both the plates will be negative

Conventional flow of current will always be from:

The drift velocity of free electrons in a conductor is ‘v’ when a current ‘i’ is flowing in it.  If both the radius and current are doubled, then drift velocity will be

(a) v

(b)

(c)

(d)

For which nucleus will the value of binding energy per nucleon be maximum?

The adjoining figure shows two bulbs B₁ and B₂ resistor R and an inductor L. When the switch S is turned off

(a) Both B1 and B2 die out promptly

(b) Both B1 and B2 die out with some delay

(c) B1 dies out promptly but B2 with some delay

(d) B2 dies out promptly but B1 with some delay

A laser beam of pulse power 10¹² watt is focussed on an object are 10^–4 cm². The energy flux in watt/ cm² at the point of focus is

(a) 1020

(b) 1016

(c) 108

(d) 104

A region surrounding a stationary electric dipoles has:

The resistance of a 5 cm long wire is 10 W.  It is uniformly stretched so that its length becomes 20 cm.  The resistance of the wire is

(a) 160 W

(b) 80 W

(c) 40 W

(d) 20 W

When a ray of light enters a glass slab its wavelength :

An object is at a distance of 0.5 m in front of a plane mirror. Distance between the object and image is

(a) 0.5 m

(b) 1 m

(c) 0.25 m

(d) 1.5 m