List of practice Questions

An electric dipole consists of two opposite charges of magnitude \(q = 1\times 10^{-6}\,C\) separated by \(2.0\,cm\). The dipole is placed in an external field of \(2\times 10^{5}\,NC^{-1}\). What maximum torque does the field exert on the dipole? How much work must an external agent do to turn the dipole end to end, starting from position of alignment (\(\theta = 0^\circ\))?

The electron of hydrogen atom is considered to be revolving round a proton in circular orbit of radius \(h^2/me^2\) with velocity \(e^2/h\), where \(h = h/2\pi\). The current \(i\) is

Which of the following rays is emitted by a human body?

A proton of mass \(1.67\times 10^{-27}\,kg\) enters a uniform magnetic field of \(1\,T\) at point \(A\) shown in figure with a speed of \(10^{7}\,m\,s^{-1}\). The magnetic field is directed perpendicular to the plane of the paper downwards. If the proton emerges out of the magnetic field at point \(C\), then the distance \(AC\) and the value of angle \(\theta\) will respectively be

A neutral water molecule (\(H_2O\)) in its vapour state has an electric dipole moment of magnitude \(6.4\times 10^{-30}\,C\,m\). How far apart are the molecules centres of positive and negative charges?

A straight wire carrying current \( i \) is turned into a circular loop. If the magnitude of magnetic moment associated with it in MKS unit is \( M \), the length of wire will be

The ratio of the amounts of heat developed in the four arms of a balance Wheatstone bridge, when the arms have resistances \(P = 100\,\Omega\), \(Q = 10\,\Omega\), \(R = 300\,\Omega\) and \(S = 30\,\Omega\) respectively is

An electric kettle takes \(4\,A\) at \(220\,V\). How much time will it take to boil \(1\,kg\) of water from temperature \(20^\circ C\)? The temperature of boiling water is \(100^\circ C\).

Magnetic field at the centre of a circular loop of area is \(B\). The magnetic moment of the loop will be

Three separate samples of a solution of a single salt gave these results. One formed a white precipitate with excess ammonia solution, one formed a white precipitate with dil. $HCl$ solution and one formed a black precipitate with $H_{2} S$. The salt could be

Liebig? method is used for the estimation of

From the top of a cliff 25 m high the angle of elevation of a tower is found to be equal to the angle of depression of the foot of the tower. The height of the tower is

Minamata disease is due to pollution of

The value of $\cos^{-1}x + \cos^{-1} \left(\frac{x}{2} + \frac{1}{2} \sqrt{3-3x^{2}}\right) ; \frac{1}{2} \le x \le 1 $ is

The slope of the tangent to the hyperbola $2x^2 - 3y^2 = 6$ at $(3, 2)$ is

The solution of differential equation $2x \frac{dy}{dx} - y = 3$ represents a family of

If $I_{m}=\int\limits_{1}^{e}(\ln x)^{m} d x$, where $m \in N$, then $I_{10}+10 I_{9}$ is equal to -

Mean of $25$ observations was found to be $78.4$. But later on it was found that $96$ was misread $69$. The correct mean is

The function $f(x) = \tan x - 4x$ is strictly decreasing on

If $A = \begin{bmatrix}1&3\\ 3&2\\ 2&5\end{bmatrix}$ and $ B = \begin{bmatrix}-1&-2\\ 0&5\\ 3&1\end{bmatrix} $ and $A + B - D = 0$ (zero matrix), then $D$ matrix will be -

The value of $\begin{vmatrix}1&2&3\\ -4&3&6\\ 2&-7&9\end{vmatrix} $ is

If $f(x)=\frac{x}{\sqrt{1+x^{2}}}$, then (fof of) ( $x$ ) is

2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, ?

Choose the correct phrasal usage of the given words:
[I.] Trace to
[II.] Sparing of
[III.] Replete with
[IV.] Wonder at \bigskip