Practice Questions

Q14.A mass m attached to free end of a spring executes SHM with a period of 1 s. If the mass is increased by 3 kg the period of oscillation increases by one second, the value of mass m is ________ kg.

Q14.Match the List-I with List-II. List I List II A AC generator I Presence of both L and C B Transformer II Electromagnetic Induction C Resonance phenomenon to occur III Quality factor D Sharpness of resonance IV Mutual Inductance Choose the correct answer from the options given below: (1) A-IV, B-II, C-I, D-III (2) A-II, B-I, C-III, D-IV (3) A-II, B-IV, C-I, D-III (4) A-IV, B-III, C-I, D-II

Q14.Choose the correct length (L) versus square of time period (T2) ) graph for a simple pendulum executing simple harmonic motion. JEE Main 2023 (01 Feb Shift 2) JEE Main Previous Year Paper (1) (2) (3) (4)

Q14.A particle is executing simple harmonic motion (SHM). The ratio of potential energy and kinetic energy of the particle when its displacement is half of its amplitude will be (1) 1 : 1 (2) 1 : 3 (3) 2 : 1 (4) 1 : 4

Q14.For the plane electromagnetic wave given by 𝐸= 𝐸0sin ( 𝜔𝑡– 𝑘𝑥) and 𝐵= 𝐵0sin ( 𝜔𝑡- 𝑘𝑥) , the ratio of average electric energy density to average magnetic energy density is 1 (1) (2) 2 2 (3) 4 (4) 1

Q14.The magnetic moments associated with two closely wound circular coils 𝐴 and 𝐵 of radius 𝑟𝐴= 10 cm and 𝑟𝐵= 20 cm respectively are equal if: (Where 𝑁𝐴, 𝐼𝐴 and 𝑁𝐵, 𝐼𝐵 are number of turn and current of 𝐴 and 𝐵 respectively) (1) 2𝑁𝐴𝐼𝐴= 𝑁𝐵𝐼𝐵 (2) 𝑁𝐴= 2𝑁𝐵 (3) 𝑁𝐴𝐼𝐴= 4𝑁𝐵𝐼𝐵 (4) 4𝑁𝐴𝐼𝐴= 𝑁𝐵𝐼𝐵

Q14.A conducting loop of radius cm is placed perpendicular to a uniform magnetic field of 0 . 5 T. The √𝜋 magnetic field is decreased to zero in 0 . 5 s at a steady rate. The induced emf in the circular loop at 0 . 25 s is: (1) emf = 1mV (2) emf = 10mV (3) emf = 100mV (4) emf = 5mV

Q14.The engine of a train moving with speed 10 m s−1 towards a platform sounds a whistle at frequency 400 Hz . The frequency heard by a passenger inside the train is: (Neglect air speed. Speed of sound in air = 330 m s−1 ) (1) 400 Hz (2) 200 Hz (3) 412 Hz (4) 388 Hz

Q14.The distance between two consecutive points with phase difference of 60° in a wave of frequency 500 Hz is 6. 0 m . The velocity with which wave is travelling is ______ km s−1 .

Q14.A particle of mass 250 g executes a simple harmonic motion under a periodic force F = (–25x) N. The particle attains a maximum speed of 4 m s−1 during its oscillation. The amplitude of the motion is ______ cm.

Q14.A guitar string of length 90 cm vibrates with a fundamental frequency of 120 Hz. The length of the string producing a fundamental of 180 Hz will be _____ cm

Q14.A wire of density 8 × 103 kg m−3 is stretched between two clamps 0. 5 m apart. The extension developed in the wire is 3. 2 × 10−4 m. If Y = 8 × 1010 N m−2 , the fundamental frequency of vibration in the wire will be _____ Hz

Q14.A person observes two moving trains, A reaching the station and B leaving the station with equal speed of 30 m s−1 . If both trains emit sounds with frequency 300 Hz, (Speed of sound : 330 m s−1 ) approximate difference of frequencies heard by the person will be : (1) 33 Hz (2) 55 Hz (3) 80 Hz (4) 10 Hz

Q14.The free space inside a current carrying toroid is filled with a material of susceptibility 2 × 10-2. The percentage increase in the value of magnetic field inside the toroid will be (1) 0 . 2% (2) 0 . 1% (3) 2% (4) 1%

Q14.In the given circuit, the current I through the battery will be (1) 2. 5 A (2) 1 A (3) 2 A (4) 1. 5 A

Q14.The energy of an electromagnetic wave contained in a small volume oscillates with (1) Double the frequency of the wave (2) The frequency of the wave (3) Half the frequency of the wave (4) Zero frequency

Q14.The amplitude of magnetic field in an electromagnetic wave propagating along 𝑦-axis is 6 . 0 × 10 – 7 T. The maximum value of electric field in the electromagnetic wave is (1) 2 × 1015 V m – 1 (2) 180 V m – 1 (3) 6 . 0 × 10 – 7 V m – 1 (4) 5 × 1014 V m – 1

Q15.Two charges of each magnitude 0. 01 C and separated by a distance of 0. 4 mm constitute an electric dipole. If → → the dipole is placed in an uniform electric field E of 10 dyne ⋅C−1 making 30∘ angle with E, the magnitude of torque acting on dipole is: (1) 4. 0 × 10−10 N m (2) 1. 0 × 10−8 N m (3) 1. 5 × 10−9 N m (4) 2. 0 × 10−10 N m

Q15.Match List I with List II List I List II A Troposphere I Approximate 65 −75 km over Earth’s surface B E-Part of Stratosphere II Approximate 300 km over Earth’s surface C F2 -Part of Thermosphere III Approximate 10 km over Earth’s surface D D-Part of Stratosphere IV Approximate 100 km over Earth’s surface Choose the correct answer from the options given below : (1) A-III, B-IV, C-II, D-I (2) A-I, B-II, C-IV, D-III (3) A-I, B-IV, C-III, D-II (4) A-III, B-II, C-I, D-IV

Q15.As shown in the figure, a point charge Q is placed at the centre of conducting spherical shell of inner radius a and outer radius b. The electric field due to charge Q in three different regions I, II and III is given by : (I : r < a, II : a < r < b, III : r > b) (1) EI = 0, EII = 0, EIII ≠0 (2) EI ≠0, EII = 0, EIII ≠0 (3) EI ≠0, EII = 0, EIII = 0 (4) EI = 0, EII = 0, EIII = 0

Q15.Considering a group of positive charges, which of the following statements is correct? (1) Net potential of the system cannot be zero at a (2) Net potential of the system at a point can be zero point but net electric field can be zero at that but net electric field can't be zero at that point point (3) Both the net potential and the net field can be (4) Both the net potential and the net electric field zero at a point cannot be zero at a point

Q15.Given below are two statements: Statement I : Out of microwaves, infrared rays and ultraviolet rays, ultraviolet rays are the most effective for the emission of electrons from a metallic surface JEE Main 2023 (13 Apr Shift 2) JEE Main Previous Year Paper Statement II : Above the threshold frequency, the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light In the light of above statements, choose the correct answer from the options given below (1) Statement I is false but Statement II is true (2) Statement I is true but Statement II is false (3) Both Statement I and Statement II are true (4) Both Statement I and Statement II are false

Q15.A dipole comprises of two charged particles of identical magnitude q and opposite in nature. The mass m of the positive charged particle is half of the mass of the negative charged particle. The two charges are separated → by a distance l . If the dipole is placed in a uniform electric field E ; in such a way that dipole axis makes a JEE Main 2023 (06 Apr Shift 2) JEE Main Previous Year Paper → very small angle with the electric field, E . The angular frequency of the oscillations of the dipole when released is given by: (1) √3qE2ml (2) √8qEml (3) √4qEml (4) √8qE3ml

Q15.If →𝐸 and →𝐾 represent electric field and propagation vectors of the EM waves in vacuum, then magnetic field vector is given by: (𝜔- angular frequency) 1 → → → → (1) 𝐾× 𝐸 (2) 𝜔𝐸× 𝐾 𝜔 (3) 𝜔→𝐾× →𝐸 (4) →𝐾× →𝐸

Q15.In a series 𝐿𝑅 circuit with 𝑋𝐿= 𝑅, power factor is 𝑃1. If a capacitor of capacitance 𝐶 with 𝑋𝐶= 𝑋𝐿 is added to the circuit the power factor becomes 𝑃2. The ratio of 𝑃1 to 𝑃2 will be : (1) 1: 3 (2) 1: √2 (3) 1: 1 (4) 1: 2