Practice Questions

Q13.For a simple harmonic motion in a mass spring system shown, the surface is frictionless. When the mass of the block is 1 kg, the angular frequency is ω1 . When the mass block is 2 kg the angular frequency is ω2 . The ratio JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper ω2 is : ω1 (1) √2 (2) 1 √2 (3) 2 (4) 12

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 rod with circular cross-section area 2 cm2 and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0 . 4 A flows in the wire windings, the total magnetic flux produced inside windings is 4π × 10-6 Wb. The relative permeability of the rod is (Given : Permeability of vacuum μ0 = 4π × 10-7 N A-2) 32 (1) 12 . 5 (2) 5 (3) 125 (4) 5 16

Q14.The ratio of speed of sound in hydrogen gas to the speed of sound in oxygen gas at the same temperature is: (1) 1 : 2 (2) 4 : 1 (3) 1 : 4 (4) 1 : 1

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.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

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.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.

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.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.A point charge 2 × 10–2 C is moved from P to S in a uniform electric field of 30 N C–1 directed along positive x-axis. If coordinates of P and S are (1, 2, 0) m and (0, 0, 0) m respectively, the work done by electric field will be (1) 1200 mJ (2) 600 mJ (3) −600 mJ (4) −1200 mJ

Q15.Match the List-I with List-II: List I List II A Microwaves I Radioactive decay of the nucleus B Gamma rays II Rapid acceleration and deceleration of electron in aerials C Radio waves III Inner shell electrons D X-rays IV Klystron valve Choose the correct answer from the options given below: (1) A-I, B-II, C-III, D-IV (2) A-IV, B-I, C-II, D-III (3) A-I, B-III, C-IV, D-II (4) A-IV, B-III, C-II, D-I Q16.‘𝑛’ polarizing sheets are arranged such that each makes an angle 45° with the proceeding sheet. An 𝐼 unpolarized light of intensity 𝐼 is incident into this arrangement. The output intensity is found to be . The 64 value of 𝑛 will be: (1) 3 (2) 6 (3) 5 (4) 4

Q15.Electric potential at a point P due to a point charge of 5 × 10−9 C is 50 V . The distance of P from the point charge is: (Assume, 1 = 9 × 109 N m2 C−2 ) 4πε0 (1) 9 cm (2) 3 cm (3) 0. 9 cm (4) 90 cm

Q15.An organ pipe 40 cm long is open at both ends. The speed of sound in air is 360 m s−1 . The frequency of the second harmonic is _ ________ Hz.

Q16.Match List-I with List II of Electromagnetic waves with corresponding wavelength range: List I List II (A) Microwave (I) 400 nm to 1 nm (B) Ultraviolet (II) 1 nm to 10–3 nm (C) X -Ray (III) 1 mm to 700 nm (D) Infra-red (IV) 0. 1 m to 1 mm Choose the correct answer from the options given below: (1) (A) −(IV), (B) −(I), (C) −(II), (D) −(III) (2) (A) −(IV), (B) −(I), (C) −(III), (D) −(II) (3) (A) −(IV), (B) −(II), (C) −(I), (D) −(III) (4) (A) −(I), (B) −(IV), (C) −(II), (D) −(III)

Q16.An object is placed at a distance of 12 cm in front of a plane mirror. The virtual and erect image is formed by the mirror. Now the mirror is moved by 4 cm towards the stationary object. The distance by which the position of image would be shifted, will be (1) 4 cm towards mirror (2) 8 cm towards mirror (3) 8 cm away from mirror (4) 2 cm towards mirror

Q16.In an electromagnetic wave, at an instant and at a particular position, the electric field is along the negative z- axis and magnetic field is along the positive x-axis. Then the direction of propagation of electromagnetic wave is: (1) positive z-axis (2) positive y-axis (3) at 45°angle from positive y -axis (4) negative y-axis

Q17.With the help of potentiometer, we can determine the value of emf of a given cell. The sensitivity of the potentiometer is (A) directly proportional to the length of the potentiometer wire (B) directly proportional to the potential gradient of the wire (C) inversely proportional to the potential gradient of the wire (D) inversely proportional to the length of the potentiometer wire Choose the correct option for the above statements: (1) B and D only (2) A and C only (3) A only (4) C only

Q17.If a source of electromagnetic radiation having power 15 kW produces 1016 photons per second, the radiation belongs to a part of spectrum is : (Take Planck constant ℎ = 6 × 10-34 J s) (1) Micro waves (2) Ultraviolet rays (3) Gamma rays (4) Radio waves

Q17.A metallic surface is illuminated with radiation of wavelength 𝜆, the stopping potential is 𝑉0. If the same 𝑉0 surface is illuminated with radiation of wavelength 2𝜆, the stopping potential becomes . The threshold 4 wavelength for this metallic surface will be (1) 3𝜆 (2) 4𝜆 (3) 3 (4) 𝜆 2𝜆 4

Q17.A small object at rest, absorbs a light pulse of power 20 mW and duration 300 ns. Assuming speed of light as 3 × 108 m s-1. The momentum of the object becomes equal to : (1) 0 . 5 × 10-17 kg m s-1 (2) 2 × 10-17 kg m s-1 (3) 3 × 10-17 kg m s-1 (4) 1 × 10-17 kg m s-1

Q17.The half life of a radioactive substance is 𝑇. The time taken, for disintegrating 7 𝑡ℎ part of its original mass will 8 be: (1) 2𝑇 (2) 3𝑇 (3) 𝑇 (4) 8𝑇

Q17.A wire of resistance 160 Ω is melted and drawn in a wire of one-fourth of its length. The new resistance of the wire will be (1) 16 Ω (2) 10 Ω (3) 640 Ω (4) 40 Ω

Q17.The energy levels of an hydrogen atom are shown below. The transition corresponding to emission of shortest wavelength is JEE Main 2023 (06 Apr Shift 1) JEE Main Previous Year Paper (1) 𝐷 (2) 𝐴 (3) 𝐵 (4) 𝐶

Q17.Ratio of thermal energy released in two resistor R and 3R connected in parallel in an electric circuit is : (1) 3 : 1 (2) 1 : 1 (3) 1 : 3 (4) 1 : 27