List of top Physics Questions

In the case of non-conservative forces, the following statement is correct:
As shown in the figure, a block of weight 20 N is connected to the top of a smooth inclined plane by a massless spring of constant \( 8\pi \, \text{Nm}^{-1} \). If the block is pulled slightly from its mean position and released, the period of oscillations is:
ablockofweight20Nis
The orbital velocity of a body near the surface of a planet 'A' is equal to escape velocity of a body from the planet 'B'. If the masses of planets A and B are same, the ratio of their radii is:
The emissivity of a perfect black body is increased to 16 times by increasing its temperature. If the initial temperature is \( T \), then final temperature of that black body is:
The temperature of the sink of a Carnot's engine is 300 K and the efficiency of the engine is 0.25. If the temperature of the source of the engine is increased by 100 K, the efficiency of the engine increases by
The specific heat capacity of a monatomic gas at constant volume is \( x % \) of its specific heat capacity at constant pressure. Then \( x \) =
In a Young's double slit experiment, if the wavelength of light is increased by 50% and the distance between the slits is doubled, then the percentage change in fringe width is:
The net electric flux due to a uniform electric field of \( 3 \times 10^3 \, \text{NC}^{-1} \) through a cube of side 20 cm oriented such that its faces are parallel to the coordinate planes is:
The drift velocity of electrons in a conducting wire connected to a cell is \( V_d \). If the length of the wire is doubled and area of cross-section is halved, then the drift velocity of electrons becomes:
The relation between permittivity of free space, the permeability of free space and speed of light is:
One of the following substances having the tendency to move from stronger region to the weaker region of the magnetic field is:
The Lenz law is associated with
The centripetal acceleration $a$ of an electron in an orbit of hydrogen and the principal quantum number $n$ of the orbit are related by
The radius of the nucleus of an atom whose mass number is 125 is
In a transistor, when the emitter current changes by 9.85 mA, the collector current changes to 9.5 mA. Then the base current is
Band width of an optical fiber is
The kinetic energy of a particle executing simple harmonic motion is
A. maximum at equilibrium position
B. constant
C. minimum at extremes positions
D. zero
E. negative
Choose the correct answer from the options given below.
A rtain physical quantity is calculated from the formula $\frac{\pi}{3}(a^2-b^2)hd$, where a, b and h are all lengths and d is density. The physical quantity being calculated is
A swimmer wants to cross a river which is flowing at a speed 'v'. If the swimmer can swim in still water at speed 'V', the direction he should swim to cross the river in least time is
The resultant magnitude of two vectors of same magnitude is equal to magnitude of either. The angle between the two vectors is
A body of mass 10 kg is kept on a rough horizontal surfa of coefficient of friction 0.3. If a horizontal for of 50 N is applied on the body, then the acleration of the body is (Acleration due to gravity $= 10 \text{ ms}^{-2}$)
The heat energy released by water of mass 2 kg when it is cooled by $10~^\circ\text{C}$ is (Specific heat capacity of water $= 4200 \text{ J kg}^{-1} \text{K}^{-1}$)
Which of the following statements regarding ntre of mass is NOT true?
A particle of mass 10 g is moving towards east with a velocity of $10 \text{ ms}^{-1}$ and another particle of mass 15 g is moving towards north with a velocity of $5 \text{ ms}^{-1}$. The magnitude of the velocity of the ntre of mass of the system of the two particles is
The sag developed in a bar of length $l$, breadth $b$, and thickness $d$ when subjected to a load $w$ at the nter is (Y -- Young's modulus of the material of the bar)