Practice Questions

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.A single slit of width a is illuminated by a monochromatic light of wavelength 600 nm . The value of a for which first minimum appears at θ = 30o on the screen will be : (1) 1. 2 μm (2) 3 μm (3) 1. 8 μm (4) 0. 6 μm

Q17.A cell of emf 90 V is connected across series combination of two resistors each of 100 Ω resistance. A voltmeter of resistance 400 Ω is used to measure the potential difference across each resistor. The reading of the voltmeter will be: (1) 40 V (2) 45 V (3) 80 V (4) 90 V

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.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 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.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.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.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.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.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

Q18.The de Broglie wavelength of an electron having kinetic energy E is λ . If the kinetic energy of electron becomes E , then its de-Broglie wavelength will be: 4 (1) √2λ (2) λ √2 (3) λ (4) 2λ 2

Q18.The angular momentum for the electron in Bohr’s orbit is 𝐿. If the electron is assumed to revolve in second orbit of hydrogen atom, then the change in angular momentum will be (1) Zero (2) 2𝐿 (3) 𝐿 (4) 𝐿 2

Q18.The H amount of thermal energy is developed by a resistor in 10 s when a current of 4 A is passed through it. If the current is increased to 16 A , the thermal energy developed by the resistor in 10 s will be (1) H (2) 16H (3) H (4) 4H 4

Q18.Speed of an electron in Bohr’s 7th orbit for Hydrogen atom is 3 . 6 × 106 m s-1. The corresponding speed of the electron in 3rd orbit, in m s-1 is : (1) 1 . 8 × 106 (2) 7 . 5 × 106 (3) 3 . 6 × 106 (4) 8 . 4 × 106

Q18.The number density of free electrons in copper is nearly 8 × 1028 m−3 . A copper wire has its area of cross- section = 2 × 10−6 m2 and is carrying a current of 3. 2 A . The drift speed of the electrons is _____ ×10−6 m s−1 .

Q19.The resistivity ( 𝜌) of semiconductor varies with temperature. Which of the following curve represents the correct behaviour? (1) (2) (3) (4)

Q19.The output from a NAND gate having inputs A and B given below will be, (1) (2) (3) (4)

Q19.The logic performed by the circuit shown in figure is equivalent to JEE Main 2023 (11 Apr Shift 1) JEE Main Previous Year Paper (1) AND (2) NOR (3) OR (4) NAND

Q19.A massage signal of frequency 3 kHz is used to modulate a carrier signal of frequency 1 . 5 MHz. The bandwidth of the amplitude modulated wave is (1) 6 MHz (2) 6 kHz (3) 3 MHz (4) 3 kHz

Q19.The effect of increase in temperature on the number of electrons in conduction band ( 𝑛𝑒) and resistance of a semiconductor will be as: JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper (1) Both 𝑛𝑒 and resistance decrease (2) Both 𝑛𝑒 and resistance increase (3) 𝑛𝑒 increases, resistance decreases (4) 𝑛𝑒 decreases, resistance increases

Q20.A solenoid of 1200 turns is wound uniformly in a single layer on a glass tube 2 m long and 0. 2 m in diameter. The magnetic intensity at the center of the solenoid when a current of 2 A flows through it is: (1) 2. 4 × 103 A m−1 (2) 1. 2 × 103 A m−1 (3) 1 A m−1 (4) 2. 4 × 10−3 A m−1

Q20.A single turn current loop in the shape of a right angle triangle with sides 5 cm, 12 cm, 13 cm is carrying a current of 2 A . The loop is in a uniform magnetic field of magnitude 0. 75 T whose direction is parallel to the current in the 13 cm side of the loop. The magnitude of the magnetic force on the 5 cm side will be 130x N . The value of x is _______.