A source of unknown frequency gives 4 beats/s when sounded with a source of known frquency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second, when sounded with a source of frequency 513 Hz. The unknown frequency is
A
240 Hz
B
260 Hz
C
254 Hz
D
246 Hz
2
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become
A
$$\left( {{{2r} \over {\sqrt 3 }}} \right)$$
B
$$\left( {{{2r} \over 3}} \right)$$
C
$${\left( {{1 \over {\sqrt 2 }}} \right)^2}$$
D
$$\left( {{r \over {\root 3 \of 2 }}} \right)$$
3
NEET 2013
MCQ (Single Correct Answer)
+4
-1
A, B and C are three points in a uniform electric field. The electric potential is
A
maximum at C
B
same at all the three points A, B and C
C
maximum at A
D
maximum at B
4
NEET 2013
MCQ (Single Correct Answer)
+4
-1
The resistances of the four arms P, Q, R and S in a Wheatstone's bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the celll will be