List of top Physics Questions

The necessary condition for an interference by two sources of light is that
The magnifying power of a compound microscope increase with
The length of the seconds pendulum is decreased by $0.3\, cm$ when it is shifted to Chennai from London. If the acceleration due to gravity at London is $ 981\,cm/{{s}^{2}}, $ the acceleration due to gravity at Chennai is (assume $ {{n}^{2}}=10 $ )
The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be
The electric flux through a closed surface area $S$ enclosing charge $Q$ is $ \phi $ . If the surface area is doubled, then the flux is
Resonant frequency of a series LCR circuit is 600 Hz. Quality factor of the circuit is 4. Band width is
What is the value of inductance L for which the current is a maximum in a series LCR circuit with $ C=10\mu F $ and $ \omega =1000\,{{s}^{-1}} $ ?
Three point charges $ +\,q,-2q $ and $ +q $ are placed at points $ (x=0,y=a,z=0), $ $ (x=0,y=0,z=0) $ and $ (x=a,y=0,z=0), $ respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are
Masses $m$ and $M$ on pulley move $0.6\, m$ in $4\, s$. What is ratio of $ \frac{m}{M} $ ?
In Ramsden eyepiece, the two planoconvex lenses each of focal length $ f $ are separated by a distance $ 12\,cm $ . The equivalent focal length (in $ cm $ ) of the eyepiece is
In a region, steady and uniform electric and magnetic fields are present. These two fields are parallel to each other. A charged particle is released from rest in this region. The path of the particle will be a :
For a system to follow the law of conservation of linear momentum during a collision, the condition is (1) total external force acting on the system is zero. (2) total external force acting on the system is finite and time of collision is negligible. (3) total internal force acting on the system is zero.
Diwali rocket is ejecting 50 g of gases/s at a velocity of 400 m/s. The accelerating force on the rocket will be
When the velocity of projection of a body is made $n$ times, its time of flight becomes $n$ times. Range of projectile does not depend on the initial velocity of a body.
The magnetic field produced by a current carrying solenoid is independent of its length and cross-sectional area. The magnetic field inside the solenoid is uniform.
The colour of the green flower seen through red glass appears to be dark. Red glass transmits only red light.
: The alternating current lags behind the e.m.f. by a phase angle of $\pi / 2$, when AC flows through an inductor. : The inductive reactance increases as the frequency of $A C$ source decreases.
An electric motor will have maximum efficiency when back emf becomes equal to half of applied emf. Efficiency of electric motor depends only on magnitude of back emf.
An object $5\, cm$ tall is placed $1\, m$ from a concave spherical mirror which has a radius of curvature of $20 \,cm$. The size of the image is
Alternating current cannot be measured by $D.C.$ ammeter because
Activity of a radioactive sample decreases to $ (1/3)^{rd} $ of its original value in 3 days. Then, 1 in 9 days its activity will become
A transverse wave propagating along x-axis is represented by $ y(x,t)=8.0\sin \left( 05\pi x-4\pi t-\frac{\pi }{4} \right) $ where $x$ is in metre and $t$ is in second. The speed of the wave is
A car of mass m moves in a horizontal circular path of radius $r\,m$. At an instant its speed is v $ ms^{ - 1 } $ and is increasing at a rate of a $ ms^{ - 2}$ . Then the acceleration of the car is
An $\alpha -$ particle of energy 5 MeV is scattered through $180 ^\circ $ by a fixed uranium nucleus. The distance of the closest approach is of the order of
A spring of spring constant $5 \times 10^3 Nm^{-1}$ is stretched initially by 5 cm from the unstretched position. Then the work required to stretch it further by another 5 cm is