In Young’s double slit experiment, a minimum is obtained when the phase difference of super imposing waves is
|
(a) Zero |
(b) (2n – 1)π |
(c) nπ |
(d) (n + 1) π |
(b) (2n – 1)π
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If the work function for a certain metal is 3.2 
joule and it is illuminated with light of frequency 8 
Hz. The maximum kinetic energy of the photo-electrons would be (h = 6.63 
|
(a) 3.2 |
(b) 8.5 |
(c) 5.3 |
(d) 3.2 |
and 
are the focal lengths of a convex lens for violet and red light respectively and 
and 
are the focal lengths of a concave lens for violet and red light respectively, then
|
(a) |
(b) |
|
(c) |
(d) |
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. |
Four charges are placed on corners of a square as shown in figure having side of 5cm. If Q is one microcoulomb, then electric field intensity at centre will be
|
(a) 1.02 |
(b) 2.04 |
|
(c) 2.04 |
(d) 1.02 |
A gate has the following truth table
|
P |
1 |
1 |
0 |
0 |
|
Q |
1 |
0 |
1 |
0 |
|
R |
1 |
0 |
0 |
0 |
The gate is
|
(a) NOR |
(b) OR |
(c) NAND |
(d) AND |
A conducting wire frame is placed in a magnetic field which is directed into the paper. The magnetic field is increasing at a constant rate. The directions of induced current in wires AB and CD are
|
(a) B to A and D to C |
(b) A to B and C to D |
|
(c) A to B and D to C |
(d) B to A and C to D |
A magnet is suspended in such a way that it oscillates in the horizontal plane. It makes 20 oscillations per minute at a place where dip angle is 30o and 15 oscillations per minute at a place where dip angle is 60o. The ratio of total earth's magnetic field at the two places is
(a) 3
|
(b) 16 : 9
|
(c) 4 : 9 |
(d) 2
|
