Recent questions tagged jeemain-2017 physics set b 08042017

Magnetic field in a plane electromagnetic wave is given by $\overrightarrow{B}= B_0 \sin (kx + \omega t) \hat{j} T$ Expression for corresponding electric field will be :
Where c is speed of light.

asked Jun 7, 2017 by priyanka.c

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A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius $b$. The two loops are in the same plane. The outer loop of radius b carries an alternating current $I=I_o \cos\; (ωt)$. The emf induced in the smaller inner loop is nearly :

asked Jun 6, 2017 by priyanka.c

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A magnetic dipole in a constant magnetic field has :

asked Jun 6, 2017 by priyanka.c

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In a certain region static electric and magnetic fields exist. The magnetic field is given by $\overrightarrow{B} = B_0 (\hat{i} + 2 \hat{j} - 4 \hat{k})$ If a test charge moving with a velocity $\overrightarrow{v} = v_0 (3 \hat{i}- \hat{j} +2 \hat{k})$ experiences no force in that region, then the electric field in the region, in $SI$ units, is :

asked Jun 6, 2017 by priyanka.c

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A $9\; V$ battery with internal resistance of $0.5\; Ω$ is connected across an infinite network as shown in the figure. All ammeters $A_1, A_2, A_3$ and voltmeter $V$ are ideal.

asked Jun 6, 2017 by priyanka.c

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What is the conductivity of a semiconductor sample having electron concentration of $5 \times 10^{18} m^{−3}$, hole concentration of $5 \times 10^{19} m^{-3}$, electron mobility of $2.0\; m^2V^{-1} s^{-1}$ and hole mobility of $0.01 m^2V^{-1}s^{-1}$?
(Take charge of electron as $1.6 \times 10^{-19}C$)

asked Jun 6, 2017 by priyanka.c

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The energy stored in the electric field produced by a metal sphere is $4.5 J$. If the sphere contains $4 µC$ charge, its radius will be : [Take : $\frac{1}{4 \pi \in_0} = 9 \times 10^9 N - m^2/C^2$]

asked Jun 6, 2017 by priyanka.c

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There is a uniform electrostatic field in a region. The potential at various points on a small sphere centred at P, in the region, is found to vary between the limits $589.0 V$ to $589.8 V$. What is the potential at a point on the sphere whose radius vector makes an angle of $60^0$ with the direction of the field ?

asked Jun 6, 2017 by priyanka.c

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Two wires $W_1$ and $W_2$ have the same radius r and respective densities $ρ_1$ and $ρ_2$ such that $ρ_2=4ρ_1$. They are joined together at the point $O$, as shown in the figure. The combination is used as a sonometer wire and kept under tension $T$. The point $O$ is midway between the two bridges. When a stationary wave is set up in the composite wire, the joint is found to be a node. The ratio of the number of antinodes formed in $W_1$ to $W_2$ is :

asked Jun 6, 2017 by priyanka.c

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The ratio of maximum acceleration to maximum velocity in a simple harmonic motion is $10^{-1}$ At, $t=0$ the displacement is $5\; m$. What is the maximum acceleration ? The initial phase is $\frac{\pi}{4}$

asked Jun 6, 2017 by priyanka.c

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An ideal gas has molecules with $5\; degrees$ of freedom. The ratio of specific heats at constant pressure $(C_p)$ and at constant volume $(C_v)$ is :

asked Jun 6, 2017 by priyanka.c

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An engine operates by taking n moles of an ideal gas through the cycle $ABCDA$ shown in figure. The thermal efficiency of the engine is : (Take Cv=1.5 R, where R is gas constant)

asked Jun 5, 2017 by priyanka.c

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If the Earth has no rotational motion, the weight of a person on the equator is W. Determine the speed with which the earth would have to rotate about its axis so that the person at the equator will weigh $\frac{3}{4} W$ Radius of the Earth is $6400 km$ and $g=10 m/s^2.$

asked Jun 5, 2017 by priyanka.c

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Moment of inertia of an equilateral triangular lamina ABC, about the axis passing through its centre O and perpendicular to its plane is Io as shown in the figure. A cavity DEF is cut out from the lamina, where D, E, F are the mid points of the sides. Moment of inertia of the remaining part of lamina about the same axis is :

asked Jun 5, 2017 by priyanka.c

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A uniform disc of radius R and mass M is free to rotate only about its axis. A string is wrapped over its rim and a body of mass m is tied to the free end of the string as shown in the figure. The body is released from rest. Then the acceleration of the body is :

asked Jun 5, 2017 by priyanka.c

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An object is dropped from a height h from the ground. Every time it hits the ground it looses 50% of its kinetic energy. The total distance covered as $t→∞$ is :

asked Jun 5, 2017 by priyanka.c

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A 1 kg block attached to a spring vibrates with a frequency of 1 Hz on a frictionless horizontal table. Two springs identical to the original spring are attached in parallel to an 8 kg block placed on the same table. So, the frequency of vibration of the 8 kg block is :

asked Jun 5, 2017 by priyanka.c

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Which graph corresponds to an object moving with a constant negative acceleration and a positive velocity ?

asked Jun 5, 2017 by priyanka.c

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