Practice Questions

Q40.Which of the following phenomena can not be explained by wave theory of light? 2025 (28 Jan Shift 2) JEE Main Previous Year Paper (1) Compton effect (2) Refraction of light (3) Reflection of light (4) Diffraction of light

Q41. A tube of length L is shown in the figure. The radius of cross section at the point (1) is 2 cm and at the point (2) is 1 cm , respectively. If the velocity of water entering at point (1) is 2 m/s, then velocity of water leaving the point (2) will be (1) 4 m/s (2) 2 m/s (3) 6 m/s (4) 8 m/s

Q42.Regarding self-inductance: A. The self-inductance of the coil depends on its geometry. B. Self-inductance does not depend on the permeability of the medium. C. Self-induced e.m.f. opposes any change in the current in a circuit. D. Self-inductance is electromagnetic analogue of mass in mechanics. E. Work needs to be done against self-induced e.m.f. in establishing the current. Choose the correct answer from the options given below: (1) A, B, C, E only (2) B, C, D, E only (3) A, C, D, E only (4) A, B, C, D only

Q42.A parallel plate capacitor was made with two rectangular plates, each with a length of l = 3 cm and breath of b = 1 cm . The distance between the plates is 3μ m . Out of the following, which are the ways to increase the capacitance by a factor of 10 ? A. l = 30 cm, b = 1 cm, d = 1μ m B. l = 3 cm, b = 1 cm, d = 30μ m C. l = 6 cm, b = 5 cm, d = 3μ m D. l = 1 cm, b = 1 cm, d = 10μ m E. l = 5 cm, b = 2 cm, d = 1μ m Choose the correct answer from the options given below: 2025 (24 Jan Shift 1) JEE Main Previous Year Paper (1) A only (2) C only (3) B and D only (4) C and E only

Q42.The pair of physical quantities not having same dimensions is : (1) Pressure and Young's modulus (2) Surface tension and impulse (3) Torque and energy (4) Angular momentum and Planck's constant

Q42.The ratio of vapour densities of two gases at the same temperature is 4 , then the ratio of r.m.s. velocities will 25 be: (1) 25 (2) 2 4 5 (3) 5 (4) 4 2 25

Q42.A solid sphere is rolling without slipping on a horizontal plane. The ratio of the linear kinetic energy of the centre of mass of the sphere and rotational kinetic energy is : (1) 3 (2) 4 4 3 (3) 5 (4) 2 2 5

Q43.Consider a parallel plate capacitor of area A (of each plate) and separation 'd' between the plates. If E is the electric field and ε0 is the permittivity of free space between the plates, then potential energy stored in the capacitor is (1) ε0E2Ad (2) 12 ε0E2Ad (3) 1 4 ε0E2Ad (4) 34 ε0E2Ad

Q43.The motion of an airplane is represented by velocity-time graph as shown below. The distance covered by airplane in the first 30.5 second is _______ km . (1) 12 (2) 3 (3) 6 (4) 9

Q43.Consider I1 and I2 are the currents flowing simultaneously in two nearby coils 1 & 2, respectively. If L1 = self inductance of coil 1, M12 = mutual inductance of coil 1 with respect to coil 2, then the value of induced emf in coil 1 will be Options (1) ε1 = −L1 dI2dt −M12 dI1dt (2) ε1 = −L1 dI1dt −M12 dI2dt (3) ε1 = −L1 dI1dt −M12 dI1dt (4) ε1 = −L1 dI1dt + M12 dI2dt

Q43.Match List - I with List - II. List - I List - II (A) Magnetic induction (I) Ampere meter 2 (B) Magnetic intensity (II) Weber (C) Magnetic flux (III) Gauss (D) Magnetic moment (IV) Ampere/meter (1) (A)-(I), (B)-(II), (C)-(III), (D)-(IV) (2) (A)-(III), (B)-(IV), (C)-(I), (D)-(II) (3) (A)-(III), (B)-(II), (C)-(I), (D)-(IV) (4) (A)-(III), (B)-(IV), (C)-(II), (D)-(I)

Q44.For a particular ideal gas which of the following graphs represents the variation of mean squared velocity of the gas molecules with temperature? 2025 (28 Jan Shift 1) JEE Main Previous Year Paper (1) (2) (3) (4)

Q44.A point charge causes an electric flux of −2 × 104Nm2C−1 to pass through a spherical Gaussian surface of 8.0 cm radius, centred on the charge. The value of the point charge is : (Given ϵ0 = 8.85 × 10−12C2 N−1 m−2 ) (1) 15.7 × 10−8C (2) 17.7 × 10−8C (3) −15.7 × 10−8C (4) −17.7 × 10−8C

Q45.In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V , what is the wavelength of the em- wave ? (Given hc = 1242eVnm where h is the Planck's constant and c is the speed of light in vaccum.) 2025 (23 Jan Shift 2) JEE Main Previous Year Paper (1) 300 nm (2) 400 nm (3) 600 nm (4) 200 nm

Q45.For an experimental expression y = 32.3×112527.4 , where all the digits are significant. Then to report the value of y we should write (1) y = 1326.19 (2) y = 1330 (3) y = 1326.186 (4) y = 1326.2

Q45.A force F = 2^i + b^j + ^k is applied on a particle and it undergoes a displacement ^i −2^j −^k. What will be the value of b, if work done on the particle is zero. (1) 0 (2) 1 2 (3) 2 (4) 1 3

Q46.A double slit interference experiment performed with a light of wavelength 600 nm forms an interference fringe pattern on a screen with 10 th bright fringe having its centre at a distance of 10 mm from the central maximum. Distance of the centre of the same 10th bright fringe from the central maximum when the source of light is replaced by another source of wavelength 660 nm would be _________ mm .

Q47.In a series LCR circuit, a resistor of 300Ω, a capacitor of 25 nF and an inductor of 100 mH are used. For maximum current in the circuit, the angular frequency of the ac source is _____ ×104 radians s−1 .

Q48.An electric dipole of dipole moment 6 × 10−6Cm is placed in uniform electric field of magnitude 106 V/m . Initially, the dipole moment is parallel to electric field. The work that needs to be done on the dipole to make its dipole moment opposite to the field, will be ____ J.

Q48.Two particles are located at equal distance from origin. The position vectors of those are represented by ¯A = 2^i + 3n^j + 2^k and ¯B = 2^i −2^j + 4p^k, respectively. If both the vectors are at right angle to each other, the value of n−1 is _____ .

Q48.The increase in pressure required to decrease the volume of a water sample by 0.2% is P × 105Nm−2 . Bulk modulus of water is 2.15 × 109Nm−2 . The value of P is … …

Q49.A container of fixed volume contains a gas at 27∘C. To double the pressure of the gas, the temperature of gas should be raised to ______ ∘C.

Q49.Two iron solid discs of negligible thickness have radii R1 and R2 and moment of intertia I1 and I2 , respectively. For R2 = 2R1 , the ratio of I1 and I2 would be 1/x, where x = ________ -

Q50.A wire of resistance 9Ω is bent to form an equilateral triangle. Then the equivalent resistance across any two vertices will be _____ ohm.

Q50.Acceleration due to gravity on the surface of earth is ' g '. If the diameter of earth is reduced to one third of its original value and mass remains unchanged, then the acceleration due to gravity on the surface of the earth is … … g.