Recent questions tagged 2017

A magnetic needle of magnetic moment $6.7 \times 10^{-2}Am^2$ and moment of inertia $7.5 \times 10^{-6}\;kg \;m^2$ is performing simple harmonic oscillations in a magnetic field of $0.01\; T$. Time taken for 10 complete oscillations is :

asked Jul 26, 2017 by meena.p

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In the above circuit the current in each resistance is :

asked Jul 26, 2017 by meena.p

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In the given circuit diagram when the current reaches steady state in the circuit,the charge on the capacitor of capacitance C will be :

asked Jul 26, 2017 by meena.p

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A capacitance of $2 \mu F$ is required in an electrical circuit across a potential difference of $1.0\; kV$. A large number of $1\; \mu F$ capacitors are available which can withstand a potential difference of not more than $300\; V$. The minimum number of capacitors required to achieve this is :

asked Jul 26, 2017 by meena.p

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An electric dipole has a fixed dipole moment $\overrightarrow{p}$, which makes angle θ with respect to x-axis. When subjected to an electric field $\overrightarrow{E_1}= E \hat i $, it experiences a torque $\overrightarrow{T_1}= \tau \hat {k}$. When subjected to another electric field $\overrightarrow{E_2}= \sqrt 3 E_1 \hat j $ it experiences a torque $\overrightarrow{T_2}= -\overrightarrow{T_1}$. The angle $\theta$ is :

asked Jul 26, 2017 by meena.p

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An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency $10\; GHz$. What is the frequency of the microwave measured by the observer ? (speed of light $=3 \times 10^8 ms^{−1}$ )

asked Jul 25, 2017 by meena.p

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A particle is executing simple harmonic motion with a time period T. At time $t=0$, it is at its position of quilibrium. The kinetic energy - time graph of the particle will look like

asked May 31, 2017 by meena.p

1 answer

The temperature of an open room of volume $30 m^3$ increases from $17^{\circ}C$ to $27^{\circ}C$ due to the sunshine. The atmospheric pressure in the room remains $1×10^5\; Pa$.If $n_i$ and $n_f$ are the number of molecules in the room before and after heating, then $n_f−n_i$ will be :

asked May 31, 2017 by meena.p

1 answer

$C_p$ and $C_v$ are specific heats at constant pressure and constant volume respectively. It is observed that $C_p−C_v=a$ for hydrogen gas $Cp−Cv=b$ for nitrogen gas The correct relation between a and b is :

asked May 31, 2017 by meena.p

1 answer

An external pressure P is applied on a cube at $0^{\circ}C$ so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and α is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by :

asked May 31, 2017 by meena.p

1 answer

A copper ball of mass $100\; gm $is at a temperature T. It is dropped in a copper calorimeter of mass $100\; gm$, filled with $170\; gm$ of water at room temperature.Subsequently, the temperature of the system is found to be $75^{\circ}C$. T is given by : (Given : room temperature$=30^{\circ}C$, specific heat of copper $=0.1\; cal/gm^{\circ}C)$

asked May 31, 2017 by meena.p

1 answer

The variation of acceleration due to gravity $g$ with distance d from centre of the earth is best represented by (R=Earth’s radius) :

asked May 30, 2017 by meena.p

1 answer

A slender uniform rod of mass M and length l is pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. The angular acceleration of the rod when it makes an angle $\theta$ with the vertical is :

asked May 30, 2017 by meena.p

1 answer

The moment of inertia of a uniform cylinder of length l and radius R about its perpendicular bisector is $I$. What is the ratio $\large\frac{l}{R}$ such that the moment of inertia is minimum ?

asked May 30, 2017 by meena.p

1 answer

A time dependent force $F=6t$ acts on a particle of mass $1\;kg$. If the particle starts from rest, the work done by the force during the first 1 sec. will be :

asked May 30, 2017 by meena.p

1 answer

A body of mass $m=10^{−2}\; kg$ is moving in a medium and experiences a frictional force $F=−kv^2$. Its initial speed is $v_0=10 ms^{−1}$. If, after $10\;s$, its energy is $\large\frac{1}{8}$$ \;mv_0^2$,the value of k will be :

asked May 29, 2017 by meena.p

1 answer

A body is thrown vertically upwards. Which one of the following graphs correctly represent the velocity vs time ?

asked May 29, 2017 by meena.p

1 answer

A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in the leg will change by a factor of :

asked May 29, 2017 by meena.p

1 answer

A die which is marked with 1, 2, 3 in red and 4, 5, 6 in green is tossed. Let A be the event 'number is even' and B be the event 'number is red' and Are A and B independent?

asked Nov 17, 2016 by priyanka.c

1 answer

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