Practice Questions

Q29.In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7 . 2 mm. Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8 . 1 mm. The wavelength of second light is _____ nm .

Q29.A Zener of breakdown voltage VZ = 8 V and maximum Zener current, IZM = 10 mA is subjected to an input voltage Vi = 10 V with series resistance R = 100 Ω . In the given circuit RL represents the variable load resistance. The ratio of maximum and minimum value of RL is _____ .

Q29.A potential barrier of 0. 4 V exists across a p-n junction. An electron enters the junction from the n -side with a speed of 6. 0 × 105 m s−1 . The speed with which electron enters the p side will be x3 × 105 m s−1 , then the value of x is _____.: (Given mass of electron = 9 × 10−31 kg, charge on electron = 1. 6 × 10−19 C.)

Q29.Two lighter nuclei combine to form a comparatively heavier nucleus by the relation given below: 2𝑋+1 2𝑋=1 4𝑌2 The binding energies per nucleon 2𝑋1 and 4𝑌2 are 1 . 1MeV and 7 . 6MeV respectively. The energy released in this process is_____ MeV.

Q29.As per the given circuit, the value of current through the battery will be _____ A. JEE Main 2022 (26 Jun Shift 1) JEE Main Previous Year Paper

Q29.The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630Å is 0. 42 V . If the threshold frequency is x × 1013 s, where x is (nearest integer): (Given, speed light = 3 × 108 m s−1 . Planck's constant = 6. 63 × 10−34 J s)

Q29.Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the two beams are π and π at points A and B respectively. The difference between the 2 3 resultant intensities at the two points is xI . The value of x will be _____ .

Q29.A conducting circular loop is placed in X −Y plane in presence of magnetic field B = (3t3ˆj 3t2ˆk) in SI unit. If the radius of the loop is 1 m, the induced emf in the loop, at time, t = 2 s is nπ V. The value of n is _____ .

Q29.A deuteron and a proton moving with equal kinetic energy enter into to a uniform magnetic field at right angle to the field. If rd and rp are the radii of their circular paths respectively, then the ratio rd will be √x : 1 where rp x is _____ .

Q29.When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is v1 . When the frequency of incident radiation is increased to five times the threshold value, the maximum velocity of emitted electron becomes v2 . If v2 = xv1 , the value of x will be _____ .

Q29.In the given circuit, the value of current IL will be _____ mA. (When RL = 1 kΩ)

Q29.The energy band gap of semiconducting material to produce violet (wavelength = 4000 Å) LED is _____ eV. (Round off to the nearest integer).

Q29. x is the ratio of energies of photons produced due to transition of an electron of hydrogen atom from its x+4 (i) third permitted energy level to the second level and (ii) the highest permitted energy level to the second permitted level. The value of x will be

Q29.The total current supplied to the circuit as shown in figure by the 5 V battery is _____ A.

Q29.In a series LCR circuit, the inductance, capacitance and resistance are 𝐿= 100 mH, C = 100 𝜇Fand 𝑅= 10 Ω respectively. They are connected to an AC source of voltage 220 V and frequency of 50 Hz. The approximate value of current in the circuit will be _____ 𝐴.

Q29.In a hydrogen spectrum λ be the wavelength of first transition line of Lyman series. The wavelength difference will be " aλ" between the wavelength of 3rd transition line of Paschen series and that of 2nd transition line of Balmer Series where a = _____.

Q30.An antenna is placed in a dielectric medium of dielectric constant 6. 25. If the maximum size of that antenna is 5. 0 mm, it can radiate a signal of minimum frequency of _____ GHz. (Given μr = 1 for dielectric medium) Q31. 120 g of an organic compound which contains only carbon and hydrogen on complete combustion gives 330 g of CO2 and 270 g of water. The percentage of carbon and hydrogen in the organic compound are respectively (1) 25 and 75 (2) 40 and 60 (3) 60 and 40 (4) 75 and 25

Q30.The cut-off voltage of the diodes (shown in figure) in forward bias is 0. 6 V. The current through the resister of 40Ω is _____ mA .

Q30.The height of a transmitting antenna at the top of a tower is 25 m and that of receiving antenna is, 49 m. The maximum distance between them, for satisfactory communication in LOS (Line-Of-Sight) is K√5 × 102 m. The value of K is _____ . (Assume radius of Earth is 64 × 105 m) [Calculate upto nearest integer value]

Q30.If the potential barrier across a p −n junction is 0. 6 V. Then the electric field intensity, in the depletion region having the width of 6 × 10−6 m , will be _____ ×105 N C−1

Q30.The current in a coil of self inductance 𝐿= 2 . 0 H is increasing according to the law 𝑖= 2sin𝑡2. Find the amount of energy spent (in J) during the period when the current changes from 0 to 2 A.

Q30.A thin prism of angle 6° and refractive index for yellow light (nY)1. 5 is combined with another prism of angle 5° and nY = 1. 55 . The combination produces no dispersion. The net average deviation (δ) produced by the combination is ( x1 ) ° . The value of x is _____ .

Q30.The one division of main scale of vernier callipers reads 1 mm and 10 divisions of Vernier scale is equal to the 9 divisions on main scale. When the two jaws of the instrument touch each other the zero of the Vernier lies to the right of zero of the main scale and its fourth division coincides with a main scale division. When a spherical bob is tightly placed between the two jaws, the zero of the Vernier scale lies in between 4. 1 cm and 4. 2 cm and 6th Vernier division coincides with a main scale division. The diameter of the bob will be _____ 10−2 cm. Q31. 250 g solution of D -glucose in water contains 10. 8% of carbon by weight. The molality of the solution is nearest to (Given: Atomic Weights are H = 1u; C = 12 u; O = 16 u ) (1) 1. 03 (2) 2. 06 (3) 3. 09 (4) 5. 40 JEE Main 2022 (27 Jul Shift 1) JEE Main Previous Year Paper

Q30.A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is _____ ×10−6 m.

Q30.In a vernier callipers, each cm on the main scale is divided into 20 equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be _____ ×10−2 mm