Atoms — Physics STD 12 Science — Question

Which among the following is true about magnetic susceptibility?

The susceptibility of paramagnetic substance is :

A far sighted man who has lost his spectacles, reads a book by looking through a small hole (3-4 mm) in a sheet of paper. The reason will be(a) Because the hole produces an image of the letters at a longer distance (b) Because in doing so, the focal length of the eye lens is effectively increased  (c)  Because in doing so, the focal length of the eye lens is effectively decreased(d) None of these

Usually the mirror installed in front of the motor driver's seat is:

When a negatively charged conductor is connected to earth

The output of OR gate is 1:

Which type of current is flowing through a circuit?

Assertion  :   The temperature coefficient of resistance is positive for metals and negative for p-type semiconductor.
Reason      : The effective charge carriers in metals are negatively charged whereas in p-type semiconductor they are positively charged.(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.

In case of a virtual and erect image, the magnification created by the mirror is: