A current I is passing through a wire having two sections P and Q of uniform diameters d and d/2 respectively. If the mean drift velocity of electrons in sections P and Q is denoted by vP and vQ respectively, then
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(a) vP = vQ |
(b) vP = |
(c) vP = |
(d) vP = 2 vQ |
(c) vP = 
vQ
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Match the List I with the List II from the combination shown. In the left side (List I) there are four different conditions and in the right side (List II), there are ratios of heat produced in each resistance for each condition :
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List I |
List II |
||
|
(I) |
Two wires of same resistance are connected in series and same current is passed through them |
(A) |
1 : 2 |
|
(II) |
Two wires of resistance R and 2R ohm are connected in series and same P.D. is applied across them |
(B) |
4 : 1 |
|
(III) |
Two wires of same resistance are connected in parallel and same current is flowing through them |
(C) |
1 : 1 |
|
(IV) |
Two wires of resistances in the ratio 1 : 2 are connected in parallel and same P.D. is applied across them |
(D) |
2 : 1 |
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(a) I – B; II – A; III – C; IV - D |
(b) I – C; II – D; III – C; IV - D |
|
(c) I – B; II – D; III – A; IV - C |
(d) I – A; II – B; III – D; IV - C |
An electron moves with a constant speed v along a circle of radius r. Its magnetic moment will be (e is the electron's charge)
|
(a) evr |
(b) |
(c) |
(d) 2πrev |
0.2 Fcapacitor is charged to 600 V by a battery. On removing the battery, it is connected with another parallel plate condenser of 1F. The potential decreases to
|
(a) 100 volts |
(b) 120 volts |
(c) 300 volts |
(d) 600 volts |
When a proton is accelerated through 1V, then its kinetic energy will be
|
(a) 1840 eV |
(b) 13.6 eV |
(c) 1 eV |
(d) 0.54 eV |
A cell of internal resistance 3 ohm and emf 10 volt is connected to a uniform wire of length 500 cm and resistance 3 ohm. The potential gradient in the wire is
|
(a) 30 mV/cm |
(b) 10 mV/cm |
(c) 20 mV/cm |
(d) 4 mV/cm |
A thin prism P1 with angle 4° and made from glass of refractive index 1.54 is combined with another thin prism P2 made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of prism P2 is
|
(a) 2.6° |
(b) 3° |
(c) 4° |
(d) 5.33° |
Assertion : The force with which one plate of a parallel plate capacitor is attracted towards the other plate is equal to square of surface density per e per unit area.
Reason : The electric field due to one charged plate of the capacitor at the location of the other is equal to surface density per e.
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(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. |
Electron volt is a unit of
|
(a) Potential |
(b) Charge |
(c) Power |
(d) Energy |
