Practice Questions

Q15.A monochromatic light wave with wavelength 𝜆1 and frequency 𝜈1 in air enters another medium. If the angle of incidence and angle of refraction at the interface are 45° and 30° respectively, then the wavelength 𝜆2 and frequency 𝜈2 of the refracted wave are: (1) 𝜆2 = √2𝜆1, 𝜈2 = 𝜈1 (2) 𝜆2 = 𝜆1, 𝜈2 = 1 √2𝜈1 (3) 𝜆2 = 𝜆1, 𝜈2 = √2𝜈1 (4) 𝜆2 = 1 𝜈2 = 𝜈1 √2𝜆1,

Q15.The ratio of intensities at two points P and Q on the screen in a Young's double slit experiment where phase difference between two waves of same amplitude are π and π respectively are 3 2, (1) 2 : 3 (2) 1 : 3 (3) 3 : 1 (4) 3 : 2

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.A 12 V battery connected to a coil of resistance 6 Ω through a switch, drives a constant current in the circuit. The switch is opened in 1 ms. The emf induced across the coil is 20 V. The inductance of the coil is : (1) 10 mH (2) 8 mH (3) 5 mH (4) 12 mH

Q15.If V is the gravitational potential due to sphere of uniform density on its surface, then its value at the centre of sphere will be: (1) 4 V (2) V 3 2 (3) V (4) 3V 2

Q15.For a certain organ pipe, the first three resonance frequencies are in the ratio of 1 : 3 : 5 respectively. If the frequency of fifth harmonic is 405 Hz and the speed of sound in air is 324 m s–1 the length of the organ pipe is _____ m .

Q15. As per the given graph, choose the correct representation for curve 𝐴 and curve 𝐵 {Where 𝑋𝐶= Reactance of pure capacitive circuit connected with A.C. source 𝑋𝐿= Reactance of pure inductive circuit connected with A.C. source 𝑅= Impedance of pure resistive circuit connected with A.C. source 𝑍= Impedance of the 𝐿𝐶𝑅 series circuit } (1) 𝐴= 𝑋𝐶, 𝐵= 𝑅 (2) 𝐴= 𝑋𝐿, 𝐵= 𝑅 (3) 𝐴= 𝑋𝐿, 𝐵= 𝑍 (4) 𝐴= 𝑋𝐶, 𝐵= 𝑋𝐿

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

Q16.Given below are two statements : Statement I : If the Brewster's angle for the light propagating from air to glass is 𝜃𝐵, then Brewster's angle for the light propagating from glass to air is 𝜋 - 𝜃𝐵. 2 Statement II : The Brewster's angle for the light propagating from glass to air is tan-1𝜇g, where 𝜇g is the refractive index of glass. In the light of the above statements, choose the correct answer from the options given below : (1) Both Statements I and Statement II are true. (2) Statement I is true but Statement II is false. (3) Both Statement I and Statement II are false. (4) Statement I is false but Statement II is true.

Q16.A capacitor of capacitance C is charged to a potential V . The flux of the electric field through a closed surface enclosing the positive plate of the capacitor is: (1) CV (2) Zero ε0 (3) 2 CV (4) CV ε0 2ε0

Q16.The kinetic energy of an electron, 𝛼- particle and a proton are given as 4𝐾, 2𝐾 and 𝐾 respectively. The de- Broglie wavelength associated with electron ( 𝜆𝑒) , 𝛼- particle ( 𝜆𝛼) and the proton (𝜆𝑝) are as follows: (1) 𝜆𝛼= 𝜆𝑝> 𝜆𝑒 (2) 𝜆𝛼< 𝜆𝑝< 𝜆𝑒 (3) 𝜆𝛼= 𝜆𝑝< 𝜆𝑒 (4) 𝜆𝛼> 𝜆𝑝> 𝜆𝑒

Q16.A person has been using spectacles of power -1 . 0 diopter for distant vision and a separate reading glass of power 2 . 0 diopters. What is the least distance of distinct vision for this person: (1) 10 cm (2) 40 cm (3) 30 cm (4) 50 cm

Q16.A parallel plate capacitor with air between the plate has a capacitance of 15 pF . The separation between the plate becomes twice and the space between them is filled with a medium of dielectric constant 3. 5 . Then the capacitance becomes x 4 pF . The value of x is____. JEE Main 2023 (24 Jan Shift 2) JEE Main Previous Year Paper

Q16.A parallel plate capacitor has plate area 40 cm2 and plates separation 2 mm . The space between the plates is filled with a dielectric medium of a thickness 1 mm and dielectric constant 5 . The capacitance of the system is: (1) 24ε0 F (2) 103 ε0 F (3) 10 3 ε0 F (4) 10ε0 F

Q16.Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R Assertion A : The beam of electrons shows wave nature and exhibit interference and diffraction. Reason R : Davisson Germer Experimentally verified the wave nature of electrons. In the light of the above statements. Choose the most appropriate answer from the options given below : (1) A is correct but R is not correct (2) A is not correct but R is correct (3) Both A and R are correct but R is Not the correct (4) Both A and R are correct and R is the correct explanation of A explanation of A

Q17.A uniform metallic wire carries a current 2 A, when 3. 4 V battery is connected across it. The mass of uniform metallic wire is 8. 92 × 10−3 kg, density is 8. 92 × 103 kg m−3 and resistivity is 1. 7 × 10−8 Ω −m The length of wire is : (1) l = 6. 8 m (2) l = 10 m (3) l = 5 m (4) l = 100 m

Q17.Different combination of 3 resistors of equal resistance R are shown in the figures. The increasing order for power dissipation is: (A) (B) JEE Main 2023 (13 Apr Shift 1) JEE Main Previous Year Paper (C) (D) (1) PB < PC < PD < PA (2) PC < PD < PA < PB (3) PC < PB < PA < PD (4) PA < PB < PC < PD

Q17.The de Broglie wavelength of a molecule in a gas at room temperature 300 K is 𝜆1. If the temperature of the gas is increased to 600 K, then the de Broglie wavelength of the same gas molecule becomes JEE Main 2023 (10 Apr Shift 1) JEE Main Previous Year Paper 1 (1) 2𝜆1 (2) √2𝜆1 (3) 1 (4) 2𝜆1 √2𝜆1

Q17.The equivalent resistance between A and B is _______. JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper . (1) 2 Ω (2) 1 Ω 3 2 (3) 3 Ω (4) 1 Ω 2 3

Q17.In a Young’s double slit experiment, the ratio of amplitude of light coming from slits is 2 : 1. The ratio of the maximum to minimum intensity in the interference pattern is (1) 9 : 4 (2) 25 : 9 (3) 2 : 1 (4) 9 : 1

Q17.The number of turns of the coil of a moving coil galvanometer is increased in order to increase current sensitivity by 50%. The percentage change in voltage sensitivity of the galvanometer will be : (1) 100% (2) 50% (3) 75% (4) 0% JEE Main 2023 (31 Jan Shift 2) JEE Main Previous Year Paper

Q17.A point charge of 10 µC is placed at the origin. At what location on the X -axis should a point charge of 40 µC be placed so that the net electric field is zero at x = 2 cm on the X -axis ? (1) x = 6 cm (2) x = 4 cm (3) x = 8 cm (4) x = –4 cm

Q17.The equivalent resistance between A and B as shown in figure is: (1) 10 kΩ (2) 5 kΩ (3) 20 kΩ (4) 30 kΩ

Q18.The current flowing through a conductor connected across a source is 2 A and 1. 2 A at 0oC and 100oC respectively. The current flowing through the conductor at 50oC will be _____ × 102 mA .

Q18.Two radioactive elements 𝐴 and 𝐵 initially have same number of atoms. The half life of 𝐴 is same as the average life of 𝐵. If 𝜆𝐴 and 𝜆𝐵 are decay constants of 𝐴 and 𝐵 respectively, then choose the correct relation from the given options. (1) 𝜆𝐴ln2 = 𝜆𝐵 (2) 𝜆𝐴= 𝜆𝐵 (3) 𝜆𝐴= 𝜆𝐵ln2 (4) 𝜆𝐴= 2𝜆𝐵