1
AIPMT 2010 Prelims
MCQ (Single Correct Answer)
+4
-1
A beam of cathode rays is subjected to crossed electric (E) and magnetic fields (B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by

(Where V is the potential difference between cathode and anode)
A
$${{{B^2}} \over {2V{E^2}}}$$
B
$${{2V{B^2}} \over {{E^2}}}$$
C
$${{2V{E^2}} \over {{B^2}}}$$
D
$${{{E^2}} \over {2V{B^2}}}$$
2
AIPMT 2010 Prelims
MCQ (Single Correct Answer)
+4
-1
A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth's horizontal magnetic field of 24 microtesla. When a horizontal field of 18 microtesla is produced opposite to the earth's field by placing a current carrying wire, the new time period of magnet will be
A
1 s
B
2 s
C
3 s
D
4 s
3
AIPMT 2010 Prelims
MCQ (Single Correct Answer)
+4
-1
Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency $$f$$ Hz. The magnitude of magnetic induction at the center of the ring is
A
$${{{\mu _0}qf} \over {2\pi R}}$$
B
$${{{\mu _0}qf} \over {2R}}$$
C
$${{{\mu _0}q} \over {2fR}}$$
D
$${{{\mu _0}q} \over {2\pi fR}}$$
4
AIPMT 2010 Prelims
MCQ (Single Correct Answer)
+4
-1
A galvanometer has a coil of resistance 100 ohm and gives a full scale deflection for 30 mA current. If it is to work as a voltmeter of 30 volt range, the resistance required to be added will be
A
900 $$\Omega $$
B
1800 $$\Omega $$
C
500 $$\Omega $$
D
1000 $$\Omega $$