List of practice Questions

A ball rolls off the top of stairway with a horizontal velocity of magnitude $1.8~m/s$. The steps are 0.20 m high and 0.20 m wide. Which step will the ball hit first?
The peak value of an alternating emf E given by $E=E₀ \cosω t$ is 10 V and its frequency is 50 Hz. At a time $t=\frac1600s$, the instantaneous value of the emf is
A circuit area 0.01 $m²$ is kept inside a magnetic field which is normal to its plane. The magnetic field changes from 2 T to 1 T in 1 ms. If the resistance of the circuit is 2 $Ω$. The amount of heat evolved is
An ideal gas expands along the path AB as shown in the p-V diagram. The work done is
If force is proportional to square of velocity, then the dimensions of proportionality constant is
Two bulbs 40 W and 60 W and rated voltage 240 V are connected in series across a potential difference of 420 V. Which bulb will work at above its rated voltage?
Two cars A and B move along a concentric circular path of radius $rA$ and $rB$ with velocities $VA$ and $VB$ maintaining constant distance, then $\fracVAVB}$ is equal to
A body of mass 10 kg is moving with a constant velocity of $10~m/s.$ When a constant force acts for 4 s on it, it moves with a velocity $2~m/s$ in the opposite direction. The acceleration produced in it is
A freshly prepared radioactive source of half-life 2 h emits radiation of intensity which is 64 times the permissible safe level. Calculate the minimum time after which it would be possible to work safely with this source.
The current in the circuit shown in the figure, considering ideal diode is
The tension in the string in the pulley system shown in the figure is
A glass flask having mass 390 g and an interior volume of 500 $cm³$ floats on water when it is less than half filled with water. The density of material of the flask is
When the wavelength of sound changes from 1 m to 1.01 m, the number of beats heard are 4. The velocity of sound is
A battery of emf 10 V is connected to resistance as shown in figure. The potential difference $VA-VB$ between the points A and B is
Solar radiation is
Fundamental frequency of an open pipe is $fₒ$. Fundamental frequency when it is half filled with water is
If the rms velocity of a gas is v, then
A sounding source of frequency 500 Hz moves towards a stationary observer with a velocity 30 m/s. If the velocity of sound in air is 330 m/s find the frequency heard by the observer.
At what height h above earth, the value of g becomes g/2? (R = Radius of earth)
In the figure shown, the magnetic field induction at the point O will be
In the electrical network shown in the figure, the potential difference across 3 $Ω$ resistance will be
Three identical thermal conductors are connected as shown in figure. Considering no heat loss due to radiation, temperature at the junction will be
r
Surface tension vanishes at
A transistor is working in common emitter mode. Its amplification factor ($β$) is 80. If the base current is 250 $μ A$, the collector current will be
From an inclined plane two particles are projected with same speed at same angle $θ$, one up and other down the plane as shown in figure, which of the following statements is/are correct?