A solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be V. If the shell is now given a charge of –3Q, the new potential difference between the same two surfaces is
|
(a) V |
(b) 2V |
(c) 4V |
(d) – 2V |
(a) V
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When a negative charge is taken at a height from earth's surface, then its potential energy
|
(a) Decreases |
(b) Increases |
|
(c) Remains unchanged |
(d) Will become infinity |
The wavelength of X-rays decreases, when
|
(a) Temperature of target is increased |
|
(b) Intensity of electron beam is increased |
|
(c) K.E. of electrons striking the target is increased |
|
(d) K.E. of electrons striking the target is decreased |
A plane convex lens is made of refractive index 1.6. The radius of curvature of the curved surface is 60 cm. The focal length of the lens is
|
(a) 50 cm |
(b) 100 cm |
(c) 200 cm |
(d) 400 cm |
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 |
Two capacitors of capacitance 2 μF and 3μF are joined in series. Outer plate first capacitor is at 1000 volt and outer plate of second capacitor is earthed (grounded). Now the potential on inner plate of each capacitor will be
|
(a) 700 Volt |
(b) 200 Volt |
(c) 600 Volt |
(d) 400 Volt |
Assertion : Newton’s rings are formed in the reflected system. When the space between the lens and the glass plate is filled with a liquid of refractive index greater than that of glass, the central spot of the pattern is dark.
Reason : The reflection is Newton’s ring cases will be from a denser to a rarer medium and the two interfering rays are reflected under similar conditions.
|
(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. |
Three charges 4q, Q and q are in a straight line in the position of 0, l/2 and l respectively. The resultant force on q will be zero, if Q =
|
(a) – q |
(b) -2q |
(c) |
(d) 4q |
