List of top Physics Questions

A battery is used to charge a parallel plate capacitor till the potential difference between the plates becomes equal to the electromotive force of the battery. The ratio of the energy stored in the capacitor and the work done by the battery will be

Ohm?? law is applicable for all conducting elements. Ohm?? law is a fundamental law.

The equivalent resistance between $A$ and $B$ (of the circuit shown) is

A $2 \,kW$ boiler used for $1\, h/$day consumes the following electrical energy in thirty days

The relation between amplification factor $ (\mu ), $ plate resistance $ ({{r}_{p}}) $ and mutual conductance $ ({{g}_{m}}) $ of a triode valve is given by

The resistance of a metallic conductor increases with temperature because

The circular motion of a panicle with constant speed is

A particle executing simple harmonic motion of amplitude $5 \,cm$ has maximum speed of $31.4 \,cm/s$. The frequency of its oscillation is

In case of a forced vibration, the resonance wave becomes very sharp when the

A particle executes SHM of amplitude 25 cm and time period 3 s. What is the minimum time required for the particle to move between two points 12.5 cm on either side of the mean position?

To make the frequency double of a spring oscillator, we have to

A large horizontal surface moves up and down in $S.H.M.$ with an amplitude of $1\, cm$. If a mass of $10\, kg$ (which is placed on the surface) is to remain continuously in contact with it, the maximum frequency of S.H.M. will be

Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then

A charge $q$ is located at the centre of a cube. The electric flux through any face is

An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The Coulomb force F between the two is $ \bigg( {where} \, k = \frac{1}{ 4 \pi \varepsilon_0}\bigg)$

A solid metallic sphere has a charge $+3 Q$. Concentric with this sphere is a conducting spherical shell having charge $-Q$. The radius of the sphere is $a$ and that of the spherical shell is $b(b>a)$. What is the electric field at a distance $R(a

In a cavity within a conductor, the electric field is zero. Charges in a conductor reside only at its surface.

If the electric flux entering and leaving an enclosed surface respectively are $\phi_1 $ and $ \phi_2$ , the electric charge inside the surface will be

Emf of generator is $6 \,V$ and internal resistance is $0.5\, k \Omega$. If internal resistance of voltmeter is $2.5\, k \Omega$. then reading of voltmeter must be

A capillary tube is attached horizontally to a constant head arrangement. If the radius of the capillary tube is increased by $10\%$, then the rate of flow of liquid will change nearly by

As per this diagram a point charge $+q$ is placed at the origin $O$. Work done in taking another point charge $-Q$ from the point $A$ [coordinates $(0, a)]$

For inside points $(r \le R) $ $E = 0\, \, \Rightarrow\, \, V =constant = \frac{1}{4 \pi\varepsilon_0} \frac{q}{R}$ For inside points $(r \ge R) $ $\hspace18mm E = \frac{1}{4 \pi\varepsilon_0}.\frac{q}{r^2}$ or $E \propto \frac{1}{r^2}$ and $\hspace10mm V = \frac{1}{4 \pi\varepsilon_0}\frac{q}{r}$ or $V \propto \frac{1}{r}$ On the surface (r = R) $\hspace20mm V = \frac{1}{4 \pi\varepsilon_0}\frac{q}{R}$ $\Rightarrow\hspace15mm E = \frac{1}{4 \pi\varepsilon_0}.\frac{q}{R^2}=\frac{\sigma}{\varepsilon_0}$ where, $ \sigma = \frac{q}{4 \pi R^2}=$ surface charge density corresponding to above equations the correct graphs are shown in option (d).

27 small drops each having charge q and radius r coalesce to from big drop. How many times charge and capacitance will become?

Charges are placed on the vertices of a square as shown. Let $\vec {E}$ be the electric field and $V$ the potential at the centre. If the charges on $A$ and $B$ are interchanged with those on $D$ and $C$ respectively, then