List of practice Questions

A body cools from 50.0°C to 49.9°C in 5s. How long will it take to cool from 40.0°C to 39.9°C? Assume the temperature of surroundings to be 30.0°C and Newton’s law of cooling to be valid:

Consider the junction diode is ideal. The value of current flowing through AB is:

A metal disc of radius 100 cm is rotated at a constant angular speed of 60 rad/s in a plane at right angles to an external field of magnetic induction 0.5 Wb/m\(^2\). The emf induced between the centre and a point on the rim will be:

Ionisation energy of \( \text{He}^+ \) is \( 19.6 \times 10^{-18} \, \text{J} \, \text{atom}^{-1} \). The energy of the first stationary state (n = 1) of \( \text{Li}^{2+} \) is:

The chirality of the compound:

Which of the following compounds is formed when a mixture of \( K_2Cr_2O_7 \) and NaCl is heated with conc. \( H_2SO_4 \)?

For the process \( H_2O(g) \, (1 \, \text{bar}, 373 \, \text{K}) \rightarrow H_2O(g) \, (1 \, \text{bar}, 373 \, \text{K}) \), the correct set of thermodynamic parameters is:

In the circuit shown the cells A and B have negligible resistances. For \( V_A = 12 \, \text{V} \), \( R_1 = 500 \, \Omega \) and \( R = 1000 \, \Omega \), the galvanometer \( G \) shows no deflection. The value of \( V_B \) is:

A steel wire of length \( \ell \) has a magnetic moment \( M \). It is then bent into a semicircular arc. The new magnetic moment is:

A running man has half the kinetic energy of that of a boy of half his mass. The man speeds up by 1m/s so as to have same K.E. as that of the boy. The original speed of the man will be:

In Young's double slit experiment the two slits are illuminated by light of wavelength 5890Å and the distance between the fringes obtained on the screen is 0.2 cm. If the whole apparatus is immersed in water then the angular fringe width will be \( \dfrac{4}{3} \). The refractive index of water is:

Four point charges \( -Q, -2Q, 2q \) and \( 4q \) are placed, one at each corner of the square. The relation between \( Q \) and \( q \) for which the potential at the centre of the square is zero is:

In the given circuit the reading of voltmeter \( V_1 \) and \( V_2 \) are 300 volt each. The reading of the voltmeter \( V_3 \) and ammeter \( A \) are respectively:

The ratio of radii of the first three Bohr orbits is:

The given electrical network is equivalent to:

A large number of liquid drops each of radius \( r \) coalesce to form a single drop of radius \( R \). The energy released in the process is converted into kinetic energy of the big drop \( M \) is given by (given, surface tension of liquid \( \sigma \)):

Find the magnetic field at \( P \) due to the arrangement shown:

The Binding energy per nucleon of \( \dfrac{3}{2} Li \) and \( \dfrac{4}{2} He \) nuclei is 5.60 MeV and 7.06 MeV, respectively.

A ray PQ incident on the refracting face BC is refracted in the prism BA as shown in the figure and emerges from the other refracting face AC as RS such that \( \angle AQ = \angle RS \). If the angle of prism \( A = 60^\circ \) and the refractive index of the material of prism is \( \sqrt{3} \), then the angle of deviation of the ray is:

In a photoelectric effect measurement, the stopping potential for a given metal is found to be \( V_0 \) volt when radiation of wavelength \( \lambda_0 \) is used. If radiation of wavelength \( 2\lambda_0 \) is used with the same metal then the stopping potential (in volt) will be:

The principle of conservation of linear momentum can be strictly applied during a collision between two particles provided the time of impact:

The current sensitivity of a moving coil galvanometer depends on:

The length of elastic string, obeying Hooke’s law, is \( \ell_1 \) metres when the tension 4N and \( \ell_2 \) metres when the tension is 5N. The length in metres when the tension is 9N is:

A square loop, carrying a steady current \( I \), is placed in a horizontal plane near a long straight conductor carrying a steady current \( I \), at a distance \( d \) from the conductor as shown in figure. The loop will experience:

The temperature of equal masses of three different liquids A, B, and C are 12°C, 19°C, and 28°C respectively. The temperature when A and B are mixed is 16°C and when B and C are mixed is 23°C. The temperature when A and C are mixed is: