List of top Physics Questions

A parallel plate capacitor is made up of stair like structure with a plate area A of each stair and that is connected with a wire of length b, as shown in the figure. The capacitance of the arrangement is \(\frac{x}{15} \frac{ε_0A}{b}\), the value of \(x\) is ______?

In the given circuit ‘a‘ is an arbitrary constant. The value of m for which the equivalent circuit resistance is minimum, will be \(\frac{\sqrt x}{2}\).The value of x is________.

The cut-off voltage of the diodes (shown in figure) in forward bias is \(0.6\; V\). The current through the resistor of \(40\) \(Ω\) is____ mA.

A metallic rod of length \(20\) cm is placed in North-South direction and is moved at a constant speed of 20 m/s towards East. The horizontal component of the Earth’s magnetic field at that place is \(4 × 10^{–3}\) T and the angle of dip is \(45º\). The emf induced in the rod is __________mV.

A deuteron and a proton moving with equal kinetic energy enter into a uniform magnetic field at right angle to the field. If \(r_d\) and \(r_p\) are the radii of their circular paths respectively, then the ratio \(\frac{r_d}{r_p}\) will be \(\sqrt x:1\) where \(x\) is__________

An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is

A proton and an alpha particle of the same velocity enter in a uniform magnetic field which is acting perpendicular to their direction of motion. The ratio of the radii of the circular paths described by the alpha particle and proton is

All resistances in figure are 1 Ω each. The value of current ‘I‘ is \((\frac{a}{5})\) A. The value of a is _______.

A capacitor C₁ of capacitance 5 μF is charged to a potential of 30 V using a battery. The battery is then removed and the charged capacitor is connected to an uncharged capacitor C₂ of capacitance 10 μF as shown in figure. When the switch is closed charge flows between the capacitors. At equilibrium, the charge on the capacitor C₂ is ____ μC.

A tuning fork of frequency 340 Hz resonates in the fundamental mode with an air column of length 125 cm in a cylindrical tube closed at one end. When water is slowly poured in it, the minimum height of water required for observing resonance once again is ____cm. (Velocity of sound in air is 340 ms^–1)

A liquid of density 750 kgm^–3 flows smoothly through a horizontal pipe that tapers in cross-sectional area from A₁ = 1.2 × 10^–2 m² to \(A_2=\frac{A_1}{2}.\) The pressure difference between the wide and narrow sections of the pipe is 4500 Pa. The rate of flow of liquid is _____ × 10^–3 m³s^–1.

300 cal. of heat is given to a heat engine and it rejects 225 cal. of heat. If source temperature is 227°C, then the temperature of sink will be _______°C.

\(\sqrt{d_1}\) and \(\sqrt{d_2}\) are the impact parameters corresponding to scattering angles 60° and 90° respectively, when an α particle is approaching a gold nucleus. For d₁ = xd₂, the value of x will be ______.

A transistor is used in an amplifier circuit in common emitter mode. If the base current changes by 100μA, it brings a change of 10mA in collector current. If the load resistance is 2kΩ and input resistance is 1kΩ, the value of power gain is \(x×10^4\). The value of x is _______.

A parallel beam of light is allowed to fall on a transparent spherical globe of diameter 30 cm and refractive index 1.5. The distance from the centre of the globe at which the beam of light can converge is________ mm.

For the network shown below, the value of V_B– V_A is ________V.

A uniform disc with mass M = 4 kg and radius R = 10 cm is mounted on a fixed horizontal axle as shown in figure.
 
A block with mass m = 2 kg hangs from a massless cord that is wrapped around the rim of the disc. During the fall of the block, the cord does not slip and there is no friction at the axle. The tension in the cord is _____ N. (Take g = 10 ms^–2)

A car covers AB distance with first one-third at velocity v₁ ms^–1, second one-third at v₂ ms^–1 and last one-third at v₃ ms^–1. If v₃ = 3v₁, v₂ = 2v₁ and v₁ = 11 ms^–1  ,then the average velocity of the car is ____ ms^–1.

A source of potential difference \(V\) is connected to the combination of two identical capacitors as shown in the figure. When key \(‘K’\) is closed, the total energy stored across the combination is \(E_1\). Now key \(‘K’\) is opened and dielectric of dielectric constant \(5\) is introduced between the plates of the capacitors. The total energy stored across the combination is now \(E_2\). The ratio \(\frac{E_1}{E_2}\) will be

Two concentric circular loops of radii \(r_1 = 30\) cm and \(r_2 = 50\) cm are placed in \(X–Y\) plane as shown in the figure. \(A\) current \(I = 7 \;A\) is flowing through them in the direction as shown in figure. The net magnetic moment of this system of two circular loops is approximately

A velocity selector consists of electric field \(\overrightarrow E=E\hat K\) and magnetic field \(\overrightarrow B=B\hat j\) with \(B = 12 \;mT\). The value of E required for an electron of energy \(728\) \(eV\) moving along the positive x-axis to pass undeflected is (Given, mass of electron = \(9.1 × 10^{–31}\) kg)

If \(\overrightarrow A=(2\hat i+3\hat j−\hat k)m\) and \(\overrightarrow B=(\hat i+2\hat j+2\hat k)m\). The magnitude of component of vector \(\overrightarrow A\) along vector \(\overrightarrow B\) will be ______\(m\).

The radius of gyration of a cylindrical rod about an axis of rotation perpendicular to its length and passing through the center will be_________m. Given the length of the rod is \(10\sqrt3\; m\).

In the given figure, the face AC of the equilateral prism is immersed in a liquid of refractive index ‘n‘. For incident angle 60° at the side AC the refracted light beam just grazes along face AC. The refractive index of the liquid n = \((\sqrt x)/4\). The value of \(x\) is _______.(Given refractive index of glass = \(1.5\))