Magnetism And Matter — Physics STD 12 Science — Question

Two batteries A and B each of e.m.f. 2 V are connected in series to an external resistance R = 1 ohm.  If the internal resistance of battery A is 1.9 ohms and that of B is 0.9 ohm, what is the potential difference between the terminals of battery A

(a) 2 V

(b) 3.8 V

(c) Zero

(d) None of the above

If the mass of neutron =1.7×10−27kg . Then the de broglie wavelength of neutron of energy 3eV is:

In  radio theraphy, X-rays are used to

(a) Detect bone fractures	(b) Treat cancer by controlled exposure
(c) Detect heart diseases	(d) Detect fault in radio receiving circuits

A hole diffuses from the p-side to the n-side in a p-n junction. This means that.

1. A bond ia broken on the n-side and the electron freed from the bond jumps to the conduction band.
2. A conduction electron on the p-side jumps to a broken bond to complete it.
3. A bond is broken on the n-side and the electron freed from the bond jumps to a broken bond on the p-side to complete it.
4. A bond is broken on the p-side and the electron freed from the bond jumps to a broken bond on the n-side to complete it.

A 100 ohm galvanometer gives full scale deflection at 10 mA.  How much shunt is required to read 100 mA

(a) 11.11 ohm

(b) 9.9 ohm

(c) 1.1 ohm

(d) 4.4 ohm

A charged particle would continue to move with a constant velocity in a region wherein:

A and B are two radioactive substances whose half lives are 1 and 2 years respectively. Initially 10 gm of A and 1 gm of B is taken. The time (approximate) after which they will have same quantity remaining is

(a) 6.62 years

(b) 5 years

(c) 3.2 years

(d) 7 years

A particle moves with a constant velocity parallel to the X-axis. Its angular momentum with respect to the origin:

1. Is zero.
2. Remains constant.
3. Goes on Increasing.
4. Goes on decreasing.

A 10   capacitor and a 20  capacitor are connected in series across a 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor

(a)

(b)

(c) 400 V

(d) 200 V

Crystal structure is studied by: