Electromagnetic Waves — Physics STD 12 Science — Question

Deviation of 5° is observed from a prism whose angle is small and whose refractive index is 1.5. The angle of prism is (a) 7.5°(b) 10°(c) 5° (d) 3.3°

A wire of resistance R is divided in 10 equal parts. These parts are connected in parallel, the equivalent resistance of such connection will be (a) 0.01 R(b) 0.1 R(c) 10 R   (d) 100 R

A bi-convex lens made of glass (refractive index 1.5) is put in a liquid of refractive index 1.7. Its focal length will(a) Decrease and change sign(b) Increase and change sign(c) Decrease and remain of the same sign(d) Increase and remain of the same sign

Transformers are used:

1. In DC circuits only.
2. In AC circuits only.
3. In both DC and AC circuits.
4. Neither in DC nor in AC circuits.

A convex mirror has a focal length f. A real object is placed at a distance f in front of it from the pole produces an image at(a) Infinity(b) f(c) f/2(d) 2f

Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called:

de-Broglie wavelength is :

A long, straight wire carries a current along the z-axis, One can find two points in the x−yplane such that:

1. The magnetic fields are equal.
2. The directions of the magnetic fields are the same.
3. The magnitudes of the magnetic fields are equal.
4. The field at one point is opposite to that at the other point.

Black hole is a (a) Hole in the ozone layer of atmosphere(b) Hole in earth's centre(c) Highly dense matter available in the atmosphere(d) Hole in troposphere