Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

Two bulbs are working in parallel order. Bulb A is brighter than bulb B. If  and   are their resistance respectively then

(a)

(b)

(c)

(d) None of these

In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be

(a) 0.5 mm

(b) 1.0 mm

(c) 1.2 mm

(d) 1.5 mm

A magnet of magnetic moment M is rotated through 360° in a magnetic field H, the work done will be

(a) MH

(b) 2MH

(c) 2πMH

(d) Zero

A very high magnetic field is applied to a stationary charge. Then the charge experiences

(a) A force in the direction of magnetic field

(b) A force perpendicular to the magnetic field

(c) A force in an arbitrary direction

(d) No force

How does the capacitance change with the effect of the dielectric when the battery remains connected across the capacitor?

Refractive index of diamond Is :

An electromagnetic wave, going through vacuum is described by. Which of the following is independent of wavelength

(a) k

(b) w

(c) k/w

(d) kw

Assertion    :  A potentiometer of longer length is used for accurate measurement.

Reason        : The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes small.

(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.

Kirchoffs law of junctions is also called the law of conservation of:

If a charged spherical conductor of radius 10 cm has potential V at a point distant 5 cm from its centre, then the potential at a point distant 15 cm  from the centre will be

(a)

(b)

(c)

(d) 3V