Practice Questions

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.

Q30.A transistor is used in an amplifier circuit in common emitter mode. If the base current changes by 100 μA , it brings a change of 10 mA in collector current. If the load resistance is 2 kΩ and input resistance is 1 kΩ, the value of power gain is x × 104 . The value of x is _____ .

Q30.The typical transfer characteristic of a transistor in CE configuration is shown in figure. A load resistor of 2 kΩ is connected in the collector branch of the circuit used. The input resistance of the transistor is 0 . 50 kΩ. The voltage gain of the transistor is

Q30.The Vernier constant of Vernier callipers is 0. 1 mm and it has zero error of (−0. 05 cm). While measuring diameter of a sphere, the main scale reading is 1. 7 cm and coinciding vernier division is 5 . The corrected diameter will be _____ ×10−2 cm.

Q30.The required height of a TV tower which can cover the population of 6 . 03 lakh is ℎ. If the average population density is 100 per square km and the radius of earth is 6400 km, then the value of ℎ will be _____ m.

Q30.In an experiment with a convex lens. The plot of the image distance (v′) against the object distance (μ′) measured from the focus gives a curve v′μ′ = 225 . If all the distances are measured in cm. The magnitude of the focal length of the lens is _____ cm.

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.A freshly prepared radioactive source of half life 2 hours 30 minutes emits radiation which is 64 times the permissible safe level. The minimum time, after which it would be possible to work safely with source, will be _____ hours.

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.A student in the laboratory measures thickness of a wire using screw gauge. The readings are 1. 22 mm, 1. 23 mm, 1. 19 mm and 1. 20 mm . The percentage error is 121x % . The value of x is _____ .

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.A modulating signal 2sin6 . 28 × 106𝑡 is added to the carrier signal 4sin12 . 56 × 109𝑡 for amplitude modulation. The combined signal is passed through a non-linear square law device. The output is then passed through a band pass filter. The bandwidth of the output signal of band pass filter will be _____ MHz.

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 an experiment of 𝐶𝐸 configuration of 𝑛- 𝑝- 𝑛 transistor, the transfer characteristics are observed as given in figure. JEE Main 2022 (25 Jun Shift 2) JEE Main Previous Year Paper If the input resistance is 200Ω and output resistance is 60Ω, the voltage gain in this experiment will be _____ .

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.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.Two ideal diodes are connected in the network as shown in figure. The equivalent resistance between A and B is _____ Ω.

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.A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 10μA and the collector current changes by 1. 5 mA . The load resistance is 5kΩ . The voltage gain of the transistor will be _____ .

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

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.A telegraph line of length 100 km has a capacity of 0. 01 μF km−1 and it carries an alternating current at 0. 5 kilo cycle per second. If minimum impedance is required, then the value of the inductance that needs to be introduced in series is _____ mH . (If π = √10 )

Q30.In the circuit shown below, maximum Zener diode current will be _____ mA .

Q31.Hemoglobin contains 0 . 34% of iron by mass. The number of Fe atoms in 3 . 3 g of hemoglobin is (Given : Atomic mass of Fe is 56u, NA in6 . 022 × 1023 mol-1) (1) 1 . 21 × 105 (2) 12 . 0 × 1016 (3) 1 . 21 × 1020 (4) 3 . 4 × 1022

Q31.Using the rules for significant figures, the correct answer for the expression 0.02858×0.112 will be: 0.5702 (1) 0. 005613 (2) 0. 00561 (3) 0. 0056 (4) 0. 006