Alternating Current — Physics STD 12 Science — Question

Image of any object formed at the retina of human eye is :

A 6kHz sinusoidal voltage is applied to a series RC circuit. The frequency of the voltage across the resistor is.

The frequency of revolution of a charged particle in a cyclotron does not depend on ‘X’. Identify X.

The amount of heat produced in a resistor when a current is passed through it can be found using

(a) Faraday’s Law

(b) Kirchhoff’s Law

(c) Laplace’s Law

(d) Joule’s Law

A concave lens and a convex lens have same focal length of 20 cm and both put in contact this combination is used to view an object 5 cm long kept at 20 cm from the lens combination. As compared to object the image will be

(a) Magnified and inverted	(b) Reduced and erect
(c) Of the same size and erect	(d) Of the same size and inverted

When Silicon is dopped with Boron as an impurity the resulting substance is :

Kinetic energy of an electron accelerated in a potential difference of 100 V is

(a) 1.6  J

(b) 1.6  J

(c) 1.6  J

(d) 1.6  J

In the depletion region of a diode:

If an electron jumps from 1st orbital to 3rd orbital, then it will

(a) Absorb energy	(b) Release energy
(c) No gain of energy	(d) None of these

Calculate the surface integral of a magnetic field over a surface.