List of top Physics Questions

The current \(i\) in the circuit given below is
current i in the circuit given below is
Two wires A and B of same material having length \(L_A, L_B\) and radii \(R_A, R_B\) and drift velocity \(V_A, V_B\) respectively carries same current. If \(L_A = L_B\) and \(R_A = 2 R_B\) then the value of \(\frac{V_A}{V_B}\) is
Two trains A and B are moving towards each other with speeds 72 kmh$^{-1}$ and 36 kmh$^{-1}$ respectively. The train-A whistles at 640 Hz frequency. Before the trains meet, frequency of sound heard by a passenger in Train-B is (Speed of sound in air = 340 ms$^{-1}$)
The movable cylindrical pistons \( P_1 \) and \( P_2 \) of a hydraulic lift are of radii 2 m and \( R \) respectively. A body of mass 32 kg on piston \( P_2 \) is supported by a body of mass 2 kg placed on piston \( P_1 \). The value of \( R \) is
The volume of a gas at 30 °C temperature and 760 mm of Hg pressure is 100 cc. Then its volume at the same temperature and 400 mm of Hg is
The coefficient of volume expansion of a material is \(5 \times 10^{-4}\ ^\circ \text{C}^{-1}\). The fractional change in its density for a \(40^\circ\text{C}\) rise in temperature is nearly
A gaseous mixture consists of 4 g of oxygen and 4 g of helium. The ratio \( \frac{C_p}{C_v} \) of the mixture is
One mole of an ideal monatomic gas undergoes the process A $\rightarrow$ B $\rightarrow$ C $\rightarrow$ D $\rightarrow$ A as shown in the graph. The work done during the process is
an ideal monatomic gas undergoes the process A → B → C → D →A
Two wires made of the same material are clamped at one end and pulled by the same force at the other end. The length and radius of the first wire are three times those of the second. If the increase in the length of the first wire is \(x\), then the increase in the length of the second wire is:
A large tank open to the atmosphere at the top and filled with water develops a small hole in the side at a point 20 m below the water level. If the rate of flow of water from the hole is \(3 \times 10^{-3}\,\text{m}^3/\text{min}\), then the area of the hole is: (Take \( g = 10\,\text{m/s}^2 \))
A rubber band catapult has initial length \(2\,\text{cm}\) and cross-sectional area \(5\,\text{mm}^2\). It is stretched to twice its length and then released to project a stone of mass \(20\,\text{g}\). The velocity of the projected stone is: (Young's modulus of rubber \( Y = 5 \times 10^8\,\text{Nm}^{-2} \))
There is a planet which is 8 times massive and 27 times denser than the earth. If \( g' \) and \( g \) are the accelerations due to gravity on the surfaces of the planet and the earth respectively, then
A block of mass \(5\,\text{kg}\) starts up a \(45^\circ\) incline with an initial kinetic energy of \(100\,\text{J}\). The coefficient of friction is \(0.5\). The distance it travels before coming to rest is:
If the earth were to suddenly shrink to \( \dfrac{1}{64} \) of its present volume, keeping mass constant, then what would be the new duration of the day?
The position of a \(3\,\text{kg}\) mass moving along the \(x\)-axis is given by \(x = 0.3 \cos (\omega t)\,\text{m}\). If \(K(t)\) denotes the kinetic energy at time \(t\), then the value of \( \dfrac{K\left( \dfrac{\pi}{60} \right)}{K\left( \dfrac{\pi}{30} \right)} \) is:
A wheel is rotating with angular speed \( \omega \). Another identical wheel with moment of inertia three times the first is initially at rest. It is suddenly coupled to the first. What fraction of the original kinetic energy is lost?
A lift raises 50 passengers of average weight \(600\,\text{N}\) each to a height of \(100\,\text{m}\) in time \(T\). If average power used is \(15\,\text{kW}\), then the value of \(T\) is:
A biker travels \( \frac{1}{3} \) of the distance \( L \) with speed \( v_1 \) and \( \frac{2}{3} \) of the distance with speed \( v_2 \). Then the average speed is:
Three blocks \( M_1, M_2, M_3 \) (\( M_1>M_2>M_3 \)) lie on a plane. The angle of inclination \( \theta \) is increased. If the coefficient of friction is the same for all, then:
Three blocks M1,M2,M3
A bar of mass \(m\) resting on a smooth horizontal plane starts moving due to a constant force \(F\). In the process of its rectilinear motion the angle \(\theta\) between the direction of this force and the horizontal varies as \(\theta = kx\), where \(k\) is a constant and \(x\) is the distance traversed by the bar from its initial position. The velocity \(v(\theta)\) of the bar as a function of the angle \(\theta\) is:
The number of significant figures in quantity \( 0.00005041 \; \text{J} \) is:
A particle is moving along x-axis with velocity \( v = \frac{1}{1 + \beta t} \). At time \( t = 0 \), the particle is at \( x = 0 \). The displacement as a function of time is:
Two electric dipoles of dipole moments 1.2 × 10–30 C-m and 2.4 × 10–30 C-m are placed in two different uniform electric fields of strength 5 × 104 NC–1 and 15 × 104 NC–1 respectively. The ratio of maximum torque experienced by the electric dipoles will be 1:x. The value of x is _______
A plane electromagnetic wave of wave interface 10W/m2 strikes a small mirror of area 20 cm2, held perpendicular to the approaching wave. The radiation force on the mirror will be:
Area of the cross-section of a wire is measured using a screw gauge. The pitch of the main scale is 0.5 mm. The circular scale has 100 divisions and for one full rotation of the circular scale, the main scale shifts by two divisions. The measured readings are listed below.
 
Measurement conditionMain scale readingCircular scale reading
Two arms of gauge touching each other without wire0 division4 divisions
Attempt-1: With wire4 divisions
20 divisions
Attempt-2: With wire
4 divisions
16 divisions

What are the diameter and cross-sectional area of the wire measured using the screw gauge?