List of top Physics Questions

Alternating current of peak value $\left(\frac{2}{\pi}\right)$ ampere flows through the primary coil of the transformer. The coefficient of mutual inductance between primary and secondary coil is 1 henry. The peak e.m.f. induced in secondary coil is (Frequency of $AC = 50\, Hz$)
A pan filled with hot food cools from $94 ^{\circ}C$ to $86^{\circ}C$ in $2$ minutes. When the room temperature is $20 ^{\circ}C$. How long will it cool from $74 ^{\circ}C$ to $66 ^{\circ}C$ ?
Two identical parallel plate air capacitors are connected in series to a battery of e.m.f. $V$. If one of the capacitor is completely filled with dielectric material of constant $K$, then potential difference of the other capacitor will become
The magnetic field intensity at the centre of cubical cage of identical wires of length ?a? due to a current I flowing as shown in the fiigure is
To find the focal length of a convex mirror, a student records the following data : The focal length of the convex lens is $f_1$ and that of mirror is $f_2$. Then taking index correction to be negligibly small, $f_1$ and $f_2$ are close to :
The magnetic field at the centre O of the arc shown in the figure is
A rectangular loop has a sliding connector PQ of length $\ell$ and resistance $R\,\Omega$ and it is moving with a speed v as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents $I_1,\, I_2$ and $I$ are
The density of a newly discovered planet is twice that of earth. The acceleration due to gravity at the surface of the planet is equal to that at the surface of the earth. If the radius of the earth is $R$, the radius of the planet would be
A length-scale $(\ell)$ depends on the permittivity $(\varepsilon)$ of a dielectric material, Boltzmann constant $\left( k _{ B }\right)$, the absolute temperature $(T)$, the number per unit volume $(n)$ of certain charged particles, and the charge $(q)$ carried by each of the particles. Which of the following expressions (s) for $\ell$ is (are) dimensionally correct?
Three particles $ P, Q $ and $ R $ are at rest at the vertices of an equilateral triangle of side $ s $ . Each of the particles starts moving with constant speed $ v \,ms^{-1}. P $ is moving along $ PQ, Q $ along $ QR $ and $ R $ along $ RP $ . The particles will meet each other at time $ t $ given by
In the following network potential at $'O'$
Variation of resistance of the conductor with temperature is as shown .The temperature co-efficient $(\alpha)$ of the conductor is
A 220 volt - 1000 watt bulb is connected across a 110 volt mains supply. The power consumed will be
Three resistances $P, Q, R$ each of $2\, \Omega$ and an unknown resistance $S$ form the four arms of a Wheatstone bridge circuit. When a resistance of $6\, \Omega$ is connected in parallel to $S$ the bridge gets balanced. What is the value of $S$ ?
In a potentiometer, auniform potential gradient of $ 0.8 \,V \,m^{-1} $ is maintained across its $ 10 \,m $ wire. The potential difference across two points on the wire located at $ 0 \,m \,65\, cm $ and $ 2 \,m\, 45 \,cm $ is
Mobility of free electrons in a conductor is
A particle executing $SHM $ has a maximum speed of $0.5 \, ms^{ -1}$ and maximum acceleration of $1.0 \, ms^{-2}$ The angular frequency of oscillation is
A cylinder of radius $R$, length $L$ and density $\rho$ floats upright in a fluid of density $\rho_0$. If it is given a small downward displacement of amplitude $x$, the time period of resulting undamped oscillation is
Time period of pendulum, on a satellite orbiting the earth, is
Three identical charges are placed at the vertices of an equilateral triangle. The force experienced by each charge, (if k = 1/4$\pi\varepsilon_{0}$) is
Two pith balls, each of mass 1.8 g are suspended from the same point by silk threads each of length 20 cm. When equal charge $Q$ is given to both the balls, they separate until the two threads become perpendicular. Then the charge $Q$ on each pith ball is $\left[\frac{1}{4\pi \varepsilon_0 }=9 \times10^{9} N m^{2} C^{-2}\right]$
A charge $Q$ is to be divided into two parts : $q$ and $Q - q$. What is the relation between $q$ and $Q$ if the two parts, when placed apart, has maximum coloumb repulsion
Three concentric metallic spherical shells of radii $R, 2R$ and $3R$ are given charges $Q_1, Q_2, Q_3$ respectively. It is found that the surface charge densities on the outer surface of the shells are equal. Then the ratio of the charges given to the shells $Q_1 : Q_2 : Q_3$ is
A charge $+q$ is placed at origin. There are two concentric spherical surfaces; $S_1$ of radius $R$ and $S_2$ of radius $2R$. Both the surfaces have their centres at the origin. Let $\phi_1$ denote the flux through $S_1$ and $\phi_2$ the flux through $S_2$. The relation between $\phi_1$ and $\phi_2$ is
The correct statement about electric dipole is