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.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.A cubical volume is bounded by the surfaces x = 0, x = a, y = 0, y = a, z = 0, z = a . The electric field in → the region is given by E = E0xˆi. Where E0 = 4 × 104 NC−1 m−1 . If a = 2 cm , the charge contained in the cubical volume is Q × 10–14 C . The value of Q is ______. (Take ϵ0 = 9 × 10−12 C2 N−1m−2 )

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.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

Q16.Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Two metallic spheres are charged to the same potential. One of them is hollow and another is solid, and both have the same radii. Solid sphere will have lower charge than the hollow one. Reason R : Capacitance of metallic spheres depend on the radii of spheres. In the light of the above statements, choose the correct answer from the options given below. (1) A is false but R is true (2) Both A and R are true and R is the correct explanation of A (3) A is true but R is false (4) Both A and R are true but R is not the correct explanation of A

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.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 train blowing a whistle of frequency 320 Hz approaches an observer standing on the platform at a speed of 66 m s−1 . The frequency observed by the observer will be (given speed of sound = 330 m s−1 ) ______ Hz.

Q16.A 600 pF capacitor is charged by 200 V supply. It is then disconnected from the supply and is connected to another uncharged 600 pF capacitor. Electrostatic energy lost in the process is _____ μJ.

Q16.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : If an electric dipole of dipole moment 30 × 10–5 C m is enclosed by a closed surface, the net flux coming out of the surface will be zero. Reason R : Electric dipole consists of two equal and opposite charges. In the light of above, statements, choose the correct answer from the options given below. JEE Main 2023 (12 Apr Shift 1) JEE Main Previous Year Paper (1) Both A and R are true and R is the correct (2) A is false but R is true explanation of A (3) A is true but R is false (4) Both A and R are true and R is NOT the correct explanation of A

Q16.A point charge q1 = 4q0 is placed at origin. Another point charge q2 = −q0 is placed at x = 12 cm. Charge of proton is q0 . The proton is placed on x-axis so that the electrostatic force on the proton in zero. In this situation, the position of the proton from the origin is ______ cm.

Q16.The critical angle for a denser-rarer interface is 45°. The speed of light in rarer medium is 3 × 108 m s-1. The speed of light in the denser medium is: (1) 3 . 12 × 107 m s-1 (2) 5 × 107 m s-1 (3) 2 . 12 × 108 m s-1 (4) √2 × 108 m s-1

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 variation of stopping potential V0 as a function of the frequency ( 𝜈) of the incident light for a metal is shown in figure. The work function of the surface is JEE Main 2023 (10 Apr Shift 2) JEE Main Previous Year Paper (1) 2 . 98 eV (2) 2 . 07 eV (3) 1 . 36 eV (4) 18 . 6 eV

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.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.Graphical variation of electric field due to a uniformly charged insulating solid sphere of radius R, with distance r from the centre O is represented by: JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper (1) Dig (2) (3) (4)

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.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.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.As shown in the figure, two parallel plate capacitors having equal plate area of 200 cm2 are joined in such a way that a ≠b. The equivalent capacitance of the combination is xε0F . The value of x is _____.

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.An electric dipole of dipole moment is 6. 0 × 10−6 C m placed in a uniform electric field of 1. 5 × 103 N C−1 in such a way that dipole moment is along electric field. The work done in rotating dipole by 180° in this field will be_______ mJ.

Q17.From the photoelectric effect experiment, following observations are made. Identify which of these are correct A. The stopping potential depends only on the work function of the metal. B. The saturation current increases as the intensity of incident light increases. C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light. D. Photoelectric effect can be explained using wave theory of light. Choose the correct answer from the options given below: (1) B, C only (2) A, C, D only (3) B only (4) A, B, D only