The n rows each containing m cells in series are joined in parallel. Maximum current is taken from this combination across an external resistance of 3W resistance. If the total number of cells used are 24 and internal resistance of each cell is 0.5 W then
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(a) m = 8, n = 3 |
(b) m = 6, n = 4 |
(c) m= 12, n = 2 |
(d) m = 2, n = 12 |
(c) m= 12, n = 2
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The frequencies of X-rays, g-rays and ultraviolet rays are respectively a, b and c. Then
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(a) a < b, b > c |
(b) a > b, b > c |
(c) a > b, b < c |
(d) a < b, b < c |
Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 second, given L = 10 mH
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(a) 1 V |
(b) 1 mV |
(c) 1 mV |
(d) 0.1 V |
The potential at a distance R/2 from the centre of a conducting sphere of radius R will be
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(a) 0 |
(b) |
(c) |
(d) |
The number of turns in the primary coil of a transformer is 200 and the number of turns in the secondary coil is 10. If 240 volt AC is applied to the primary, the output from the secondary will be
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(a) 48 V |
(b) 24 V |
(c) 12 V |
(d) 6 V |
The continuous x-ray spectrum obtained from a Coolidge tube is of the form
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(a)
|
(b)
|
(b)
|
(d)
|
Wires 1 and 2 carrying currents 
and 
respectively are inclined at an angle θ to each other. What is the force on a small element dl of wire 2 at a distance of r from wire 1 (as shown in figure) due to the magnetic field of wire1
|
(a) |
(b) |
(c) |
(d) |
Assertion : Penetrating power of X-rays increases with the increasing the wavelength.
Reason : The penetrating power of X-rays increases with the frequency of X-rays.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If assertion is false but reason is true. |
