List of top Physics Questions

Specific gravity of a fluid is a dimensionless quantity. It is the ratio of density of fluid to the density of water.
An astronomical telescope has two lenses of focal powers $0.5\, D$ and $20\, D$. Then its magnifying power will be :
An annular ring with inner and outer radii $R_1$ and $R_2$ is rolling without slipping with a uniform angular speed. The ratio of the forces experienced by the two particles situated on the inner and outer parts of the ring, $\frac{F_{1}}{F_{2}}$ is :
A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity, then :
A thin glass (refractive index 1.5) lens has optical power of $- 5\, D$ in air. Its optical power in a liquid medium with refractive index 1.6 will be :
A steel scale measures the length of a copper wire as $80.0\, cm$, when both are at $20^{\circ} C$, the calibration temperature for the scale. What would the scale read for the length of the rod when both are at $40^{\circ} C ?$ Given: $\alpha$ for steel $=11 \times 10^{-6}$ per ${ }^{\circ} C$ and $\alpha$ for $Cu =11 \times 10^{-6} \text{per} ^{\circ} C$
A solid sphere is rolling on a frictionless surface, shown in figure with a translational velocity $v\, m/s$. If it is to climb the inclined surface then $v$ should be
In a semiconductor diode, the barrier potential offers opposition to only:
A parachutist after bailing out falls $50\, m$ without friction. When parachute opens, it decelerates at $2\,m/s^2$. He reaches the ground with a speed of $3 \,m/s$. At what height, did he bail out ?
A packet is dropped from a balloon which is going upwards with the velocity $12\, m$ $s^{-1}$, the velocity of the packet after 2 s will be
A nuclei $X$ with mass number $A$ and charge number $Z$, disintegrates into one $\alpha$-particle and one $\beta$-particle. The resulting nuclide $R$ has atomic mass and atomic number, equal to :
A moving coil galvanometer has $150$ equal divisions. Its current sensitivity is $10$ divisions per milliampere and voltage sensitivity is $2$ divisions per millivolt. In order that each division reads $1 V$, the resistance in Ohm?s needed to be connected in series with the coil will be :
A magnet is made to oscillate with a particular frequency, passing through a coil as shown in figure. The time variation of the magnitude of e.m.f. generated across the coil during one cycle is
A ladder is leaned against a smooth wall and it is allowed to slip on a frictionless floor. Which figure represents trace of its centre of mass.
A horizontal platform is rotating with uniform angular velocity around the vertical axis passing through its center. At some instant of time a viscous fluid of mass $m$ is dropped at the center and is allowed to spread out and finally fall. The angular velocity during this period
A hot electric iron has a resistance of $80\, \Omega$ and is used on a $200\, V$ source. The electrical energy spent, if it is used for $2\, hr$, will be :
Two radioactive substances $A$ and $B$ have decay constants 5 $\lambda$, and $\lambda$ respectively. At $t\, =\, 0$, they have the same number of nuclei. The ratio of number of nuclei of $A$ to those of $B$ will be $(1/e^2)$ after a time
If both the mass and radius of earth decrease by $1\%$, the value of (I) acceleration due to gravity would increase by $1\%$ (II) acceleration due to gravity would decrease by $1\%$ (III) escape velocity from earth's surface would decrease by $1 \%$ (IV) the gravitational potential energy of a body on earth's surface will remain unchanged
A small body of mass $m$ slides without friction from the top of a hemisphere of radius $r$. At what height will the body be detached from the centre of the hemisphere?
The objectives with large apertures are used in telescopes for
The angular speed of a body changes from $\omega_1$ to $ \omega_2$ without applying a torque, but due to change in moment of inertia. The ratio of radii of gyration in the two cases is
A faulty thermometer has its fixed point marked as $5^{\circ}$ and $95^{\circ}$. The temperature of a body as measured by the faulty thermometer is $59^{\circ}$. The correct temperature of the body on Celsius scale is
How long will a passenger sitting at the window of a train travelling at a speed of 54 km$h^{-1}$ see a train,passing by in the opposite direction with a speed of 36 km$h^{-1}$ , if the length of the second train is 150 m?
If a, b, c and d are mass, length, time and current respectively, then $b^2 \, a/ c^3$ d has the dimensions of
A conducting ring of radius $1\, m$ is placed in an uniform magnetic field $B$ of $0.01\, T$ oscillating with frequency $100\, Hz$ with its plane at right angle to $B$. What will be the induced electric field?