List of practice Questions

Soap solution is used for cleaning dirty clothes because
The refraction of light ray takes place from air to water, water to glass and again glass to air. The ray emerges parallel to incident ray. The correct relation is [\(n_a, n_w, n_g\) represent refractive indices of air, water and glass respectively]
A constant torque of 200 N m turns a flywheel, which is at rest, about an axis through its centre and perpendicular to its plane. If its moment of inertia is \(50 \, \text{kg m}^2\), then in 4 second, what will be change in its angular momentum?
If a unit vector is represented as \( \vec{u} = 0.4\hat{i} + 0.7\hat{j} + c\hat{k} \), then the value of \(c\) is
What should be the length of a closed pipe to produce resonance with sound wave of wavelength 62 cm, in fundamental mode? (Neglect end correction)
A force \(F\) of same magnitude is applied tangentially on upper and lower face of a cube, in opposite directions. Side of the cube is \(L\). The upper face of the cube shifts parallel to itself by a distance \(x_1\). If another cube of same material but side \(2L\) is subjected to the above condition, then the displacement of the top layer is
A concave mirror of focal length \(f_1\) is placed at a distance \(d\) from a convex lens of focal length \(f_2\). A parallel beam of light coming from infinity parallel to principal axis falls on the convex lens and then after refraction falls on the concave mirror. If it is to retrace the path, the distance \(d\) should be
The fundamental frequency of a sonometer wire is 50 Hz for some length and tension. If the length is increased by 25% by keeping tension same, then frequency change of second harmonic is
If the radius of the spherical Gaussian surface is increased then the electric flux due to a point charge enclosed by the surface
A closed pipe containing liquid showed a pressure \(P_1\) by gauge. When the valve is opened, pressure was reduced to \(P_2\). The speed of water flowing out of the pipe is ( \(\rho\) = density of water )
A charged particle is always moving parallel to the direction of magnetic field. The magnetic force acting on the particle will be
Young's double slit experiment is performed in water instead of air, then fringe width
A particle executes uniform circular motion with angular momentum \(L\). Its rotational kinetic energy becomes half when the angular frequency is doubled. Its new angular momentum is
When a mass \(m\) is suspended from a spring of length \(\ell\), the length of the spring becomes \(L\). The mass is pulled down by a distance \(d\) and released. If the equation of motion of the mass is \( \frac{d^2x}{dt^2} + Px = 0 \), then \(P\) is equal to ( \(g\) = acceleration due to gravity )
I–V characteristics for a junction diode is shown. The device is
An alternating current of frequency 50 Hz has the peak value as 14.14 A. The time taken by the alternating current in reaching from zero to maximum value and r.m.s. value of current will be respectively
A shell of mass \(M\) initially at rest suddenly explodes into three fragments. Two of these fragments are of mass \(M/4\) each, which move with velocities \(3 \, \text{m s}^{-1}\) and \(4 \, \text{m s}^{-1}\) respectively in mutually perpendicular directions. The magnitude of velocity of the third fragment is
Identify the oxidising agent in the following reaction.
\[ CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l) \]
Which of the following formulae is used to find edge length of bcc unit cell?
Prolonged heating of glucose with HI to form n-Hexane confirms
When will the change in Gibb’s free energy always be negative?
The conductivity of NaI solution is \( 6.0 \times 10^{-4} \, \Omega^{-1} \text{cm}^{-1} \) and molar conductivity is \( 120 \, \Omega^{-1} \text{cm}^2 \text{mol}^{-1} \). Calculate the concentration of NaI solution.
Which among the following catalysts is used in manufacture of sulphuric acid by contact process?
A balloon contains 2.27 L air and has a pressure of \(1.013 \times 10^5 \, \text{Nm}^{-2}\). The balloon rises to a certain height and expands to a volume of 4540 mL. What is the final pressure of air in the balloon?
Heat of combustion of liquid benzene to carbon dioxide and water is \(-3266 \, \text{kJ/mol}\). What is the amount of heat liberated when 780 mg of benzene is fully oxidised? (At mass of C = 12, H = 1)