1
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
Four identical point masses, each of mass m and carrying charge + q are placed at the corners of a square of sides a on a frictionless plane surface. If the particles are released simultaneously, the kinetic energy of the system when they are infinitely far apart is
A
$${{{q^2}} \over a}(2\sqrt 2 + 1)$$
B
$${{{q^2}} \over a}(\sqrt 2 + 2)$$
C
$${{{q^2}} \over a}(\sqrt 2 + 4)$$
D
$${{{q^2}} \over a}(\sqrt 2 + 1)$$
2
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
A very long charged solid cylinder of radius a contains a uniform charge density p. Dielectric constant of the material of the cylinder is K. What will be the magnitude of electric field at a radial distance x (x < a) from the axis of the cylinder?
A
$$p{x \over {{\varepsilon _0}}}$$
B
$$p{x \over {{2k\varepsilon _0}}}$$
C
$$p{{{x^2}} \over {2a{\varepsilon _0}}}$$
D
$$p{{{x^{}}} \over {2k}}$$
3
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
A galvanometer can be converted to a voltmeter of full scale deflection V0 by connecting a series resistance R1 and can be converted to an ammeter of full scale deflection I0 by connecting a shunt resistance R2. What is the current flowing through the galvanometer at its full scale deflection?
A
$${{{V_0} - {I_0}{R_2}} \over {{R_1} - {R_2}}}$$
B
$${{{V_0} + {I_0}{R_2}} \over {{R_1} + {R_2}}}$$
C
$${{{V_0} - {I_0}{R_1}} \over {{R_2} - {R_1}}}$$
D
$${{{V_0} + {I_0}{R_1}} \over {{R_1} + {R_2}}}$$
4
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
WB JEE 2020 Physics - Magnetism Question 30 English
As shown in the figure, a single conducting wire is bent to form a loop in the form of a circle of radius r concentrically inside a square of side a, where a : r = 8 : $$\pi $$. A battery B drives a current through the wire. If the battery B and the gap G are of negligible sizes, determine the strength of magnetic field at the common centre O.
A
$${{{\mu _0}I} \over {2\pi a}}\sqrt 2 (\sqrt 2 - 1)$$
B
$${{{\mu _0}I} \over {2\pi a}} (\sqrt 2 + 1)$$
C
$${{{\mu _0}I} \over {\pi a}}2\sqrt 2 (\sqrt 2 + 1)$$
D
$${{{\mu _0}I} \over {\pi a}}2\sqrt 2 (\sqrt 2 $$ - $$ 1)$$
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