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When a torque acting upon a system is zero, then which of the following will be constant?
When a body of mass $m$ just begins to slide as shown, match List-I with List-II: **List-I** (a) Normal reaction (b) Frictional force ($f_s$) (c) Weight ($mg$) (d) $mg \sin \theta$ **List-II** (i) $P$ (ii) $Q$ (iii) $R$ (iv) $S$
Two parallel metal plates having charges +Q and -Q faces each other at a certain distance between them. If the plates are now dipped in kerosene oil tank, the electric field between the plates will
A cylinder of radius R and length L is placed in a uniform electric field E parallel to the cylinder axis. The total flux for the surface of the cylinder is given by
The V-I graph for a conductor at temperatures $T_1$ and $T_2$ are as shown in the figure. The term $(T_2 - T_1)$ is proportional to:
$\varepsilon_0$ and $\mu_0$ are the electric permittivity and magnetic permeability of free space respectively. If the corresponding quantities of a medium are $2\varepsilon_0$ and $1.5\mu_0$ respectively, the refractive index of the medium will nearly be:
A hollow cylinder has a charge q coulomb within it (at the geometrical centre). If ϕ is the electric flux in units of Volt-meter associated with the curved surface B, the flux linked with the plane surface A in units of volt-meter will be:
In which of the following devices, the eddy current effect is not used?
Calculate the acceleration of the block and trolley system shown in the figure. The coefficient of kinetic friction between the trolley and the surface is $0.05$. (Take $g=10 \text{ m/s}^2$, the mass of the string is negligible and no other friction exists). [Note: Based on the answer, the mass of the hanging block is $2 \text{ kg}$ and the mass of the trolley is $10 \text{ kg}$].
A horizontal force $10 \text{ N}$ is applied to a block A as shown in figure. The mass of blocks A and B are $2 \text{ kg}$ and $3 \text{ kg}$, respectively. The blocks slide over a frictionless surface. The force exerted by block A on block B is:
A rectangular, a square, a circular and an elliptical loop, all in the $(x-y)$ plane, are moving out of a uniform magnetic field with a constant velocity, $\vec{v} = v\hat{i}$. The magnetic field is directed along the negative $z$-axis direction. The induced emf, during the passage of these loops, out of the field region, will not remain constant for:
A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of $80.0 \, \mu\text{C/m}^2$. The charge on the sphere is:
In a meter bridge experiment, the null point is at a distance of 30 cm from A. If a resistance of 16 Ω is connected in parallel with resistance Y, the null point occurs at 50 cm from A. The value of the resistance Y is:
Six charges, three positive and three negative of equal magnitude are to be placed at the vertices of a regular hexagon (P, Q, R, S, T, U) such that the electric field at the center O is double the electric field when only one positive charge of same magnitude is placed at R. Which of the following arrangements of charges is possible for P, Q, R, S, T and U respectively?
A conducting sphere of radius 10 cm has an unknown charge. If the electric field, 20 cm from the centre of the sphere is $1.5 \times 10^3$ N/C and points radially inward, what is the net charge on the sphere?
The electric field at the surface of a black box indicates that the net outward flux through the surface of the box is $8.0 \times 10^3$ Nm$^2$/C. What is the net charge inside the box?
A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is:
A polythene piece rubbed with wool is found to have a negative charge of $3 \times 10^{-7}$ C. The transfer of mass from wool to polythene is:
Two infinitely long parallel conducting plates having surface charge densities +σ and −σ respectively, are separated by a small distance. The medium between the plates is a vacuum. If ε₀ is the dielectric permittivity of vacuum, then the electric field in the region between the plates is:
The figure shows a 2.0 V potentiometer used for the determination of the internal resistance of a 1.5 V cell. The balance point of the cell in the open circuit is 76.3 cm. When a resistor of 9.5 Ω is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. The internal resistance of the cell is: