1
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
A particle with charge q moves with a velocity v in a direction perpendicular to the directions of uniform electric and magnetic fields, E and B respectively, which are mutually perpendicular to each other. Which one of the following gives the condition for which the particle moves undeflected in its original trajectory?

WB JEE 2019 Physics - Magnetism Question 25 English
A
$$v = {E \over B}$$
B
$$v = {B \over E}$$
C
$$v = \sqrt {{E \over B}} $$
D
$$v = q{B \over E}$$
2
WB JEE 2019
MCQ (Single Correct Answer)
+2
-0.5
Change Language
A parallel plate capacitor in series with a resistance of 100$$\Omega $$, an inductor of 20 mH and an AC voltage source of variable frequency shows resonance at a frequency of $${{1250} \over \pi }$$ Hz. If this capacitor is charged by a DC voltage source to a voltage 25 V, what amount of charge will be stored in each plate of the capacitor?
A
0.2 $$\mu$$C
B
2 mC
C
0.2 mC
D
0.2 C
3
WB JEE 2019
MCQ (More than One Correct Answer)
+2
-0
Change Language
Electrons are emitted with kinetic energy T from a metal plate by an irradiation of light of intensity J and frequency v. Then, which of the following will be true?
A
T $$ \propto $$ J
B
T linearly increasing with v
C
T $$ \propto $$ time of irradiation
D
Number of electrons emitted $$ \propto $$ J
4
WB JEE 2019
MCQ (More than One Correct Answer)
+2
-0
Change Language
The initial pressure and volume of a given mass of an ideal gas with $$\left( {{{{C_p}} \over {{C_V}}} = \gamma } \right)$$, taken in a cylinder fitted with a piston, are p0 and V0 respectively. At this stage the gas has the same temperature as that of the surrounding medium which is T0. It is adiabatically compressed to a volume equal to $${{{V_0}} \over 2}$$. Subsequently the gas is allowed to come to thermal equilibrium with the surroundings. What is the heat released to the surrounding?
A
0
B
$$({2^{\gamma - 1}} - 1){{{p_0}V} \over {\gamma - 1}}$$
C
$$\gamma {p_0}{V_0}In2$$
D
$${{{p_0}V} \over {2(\gamma - 1)}}$$
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