List of top Physics Questions

A series LCR circuit containing a 5.0 H inductor, 80 µF capacitor and 40 Ω resistor is connected to a 230 V variable frequency ac source. The angular frequencies of the source at which power transferred to the circuit is half the power at the resonant angular frequency are likely to be

From a circular ring of mass ‘M’ and radius ‘R’ an arc corresponding to a 90\(^{\circ}\) sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is ‘K’ times ‘MR² ’. Then the value of ‘K’ is

Two conducting circular loops of radii R₁ and R₂ are placed in the same plane with their centers coinciding. If R₁ > > R₂, the mutual inductance M between them will be directly proportional to

A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of

A uniform conducting wire of length 12a and resistance ‘R’ is wound up as a current-carrying coil in the shape of, 
(i) an equilateral triangle of side ‘a’. 
(ii) a square of side ‘a’. 
The magnetic dipole moments of the coil in each case respectively are:

In the product \(\vec{F}=q(\vec{v}\times\vec{b})\) 
=\(q\vec{v}\times(B\hat i+B \hat j+B_0\hat k)\)
 For q=1 and \(\vec v = 2\hat i+4\hat j+6\hat k\) and \(\vec F=4\hat i-20\hat j+12\hat k\)
What will be the complete expression for \(\vec B\)  ?

The total capacity of the system of capacitors shown in the adjoining figure between the points A and B is

In the circuit, a metal filament lamp is connected in series with a capacitor of capacitance $C\, \mu F$ across a $200\, V , 50\, Hz$ supply The power consumed by the lamp is $500\, W$ while the voltage drop across it is $100\, V$ Assume that there is no inductive load in the circuit Take $r m s$ values of the voltages The magnitude of the phase-angle (in degrees) between the current and supply voltage is $\phi $ Assume, $\pi \sqrt{3} \approx 5$ The value of $\phi$ is _____

The radius of a circular plate is 1.05 m. Its area (in $m^2$) up to correct significant figures is

For a prism of prism angle 𝜃 = 60°, the refractive indices of the left half and the right half are, respectively, 𝑛₁ and 𝑛₂ (𝑛₂ ≥ 𝑛₁) as shown in the figure. The angle of incidence 𝑖 is chosen such that the incident light rays will have minimum deviation if 𝑛₁  = 𝑛₂  = 𝑛 = 1.5. For the case of unequal refractive indices, 𝑛₁  = 𝑛 and 𝑛₂ = 𝑛 +∆𝑛 (where∆𝑛≪𝑛), the angle of emergence \(𝑒 =𝑖+∆𝑒\). Which of the following statement(s) is (are) correct?

The distance between two stars of masses 3M_S and 6M_S is 9R. Here R is the mean distance between the centres of the Earth and the Sun, and M_S is the mass of the Sun. The two stars orbit around their common centre of mass in circular orbits with period nT, where T is the period of Earth’s revolution around the Sun. The value of n is ___.

In the circuit shown below, the switch $S$ is connected to position $P$ for a long time so that the charge on the capacitor becomes $q _{1}\, \mu C$ Then $S$ is switched to position $Q$ After a long time, the charge on the capacitor is $q _{2}\, \mu C$ 
The magnitude of $q_2$ is ____

In order to measure the internal resistance r₁ of a cell of emf E, a meter bridge of wire resistance R₀ = 50 Ω, a resistance \(\frac{R_0}{2}\), another cell of emf \(\frac{E}{2}\) (internal resistance r) and a galvanometer G are used in a circuit, as shown in the figure. If the null point is found at l = 72 cm, then the value of r ₁ = ____

In the circuit shown below, the switch $S$ is connected to position $P$ for a long time so that the charge on the capacitor becomes $q _{1}\, \mu C$ Then $S$ is switched to position $Q$ After a long time, the charge on the capacitor is $q _{2}\, \mu C$ The magnitude of $q_1$is ____

 

A projectile is thrown from a point $O$ on the ground at an angle $45^{\circ}$ from the vertical and with a speed $5 \sqrt{2} \,m / s$. The projectile at the highest point of its trajectory splits into two equal parts. One part falls vertically down to the ground, $05\, s$ after the splitting. The other part, $t$ seconds after the splitting, falls to the ground at a distance $x$ meters from the point $O$. The acceleration due to gravity $g =10 \,m / s ^{2}$. The value of $t$ is ____

A heavy nucleus $Q$ of half-life $20$ minutes undergoes alpha-decay with probability of $60 \%$ and beta-decay with probability of $40 \%$. Initially, the number of $Q$ nuclei is $1000 $. The number of alpha-decay of $Q$ in the first one hour is

An extended object is placed at point O, 10 cm in front of a convex lens L1 and a concave lens L2 is placed 10 cm behind it, as shown in the figure. The radii of curvature of all the curved surfaces in both the lenses are 20 cm. The refractive index of both the lenses is 1.5. The total magnification of this lens system is

An ideal gas undergoes a four step cycle as shown in the $P-V$ diagram below During this cycle, heat is absorbed by the gas in

The smallest division on the main scale of a Vernier calipers is $01 \,cm$ Ten divisions of the Vernier scale correspond to nine divisions of the main scale The figure below on the left shows the reading of this calipers with no gap between its two jaws The figure on the right shows the reading with a solid sphere held between the jaws The correct diameter of the sphere is

A Soft plastic bottle, filled with water of density $1\, gm / cc$, carries an inverted glass test-tube with some air (ideal gas) trapped as shown in the figure The test-tube has a mass of $5\, gm$, and it is made of a thick glass of density $25 \,gm / cc$ Initially the bottle is sealed at atmospheric pressure $p _{0}=10^{5} \,Pa$ so that the volume of the trapped air is $v _{0}=33\, cc$ When the bottle is squeezed from outside at constant temperature, the pressure inside rises and the volume of the trapped air reduces It is found that the test tube begins to sink at pressure $p _{0}+\Delta p$ without changing its orientation At this pressure, the volume of the trapped air is $v _{0}-\Delta v$ Let $\Delta v = X \,\,cc$ and $\Delta p = Y \times 10^{3} Pa$ The value of $X$ is _______

A thermally insulating cylinder has a thermally insulating and frictionless movable partition in the middle, as shown in the figure below On each side of the partition, there is one mole of an ideal gas, with specific heat at constant volume, $C _{ V }=2 R$ Here, $R$ is the gas constant Initially, each side has a volume $V _{0}$ and temperature $T_{0}$ The left side has an electric heater, which is turned on at very low power to transfer heat $Q$ to the gas on the left side As a result the partition moves slowly towards the right reducing the right side volume to $V _{0} / 2$ Consequently, the gas temperatures on the left and the right sides become $T _{ L }$ and $T _{ R }$, respectively Ignore the changes in the temperatures of the cylinder, heater and the partition The value of $\frac{ T _{ R }}{ T _{0}}$ is

In the circuit, a metal filament lamp is connected in series with a capacitor of capacitance $C\, \mu F$ across a $200\, V , 50\, Hz$ supply The power consumed by the lamp is $500\, W$ while the voltage drop across it is $100\, V$ Assume that there is no inductive load in the circuit Take $r m s$ values of the voltages The magnitude of the phase-angle (in degrees) between the current and supply voltage is $\phi $ Assume, $\pi \sqrt{3} \approx 5$ The value of $\phi$ is _____