Practice Questions

Q24.A string of area of cross-section 4 mm2 and length 0. 5 is connected with a rigid body of mass 2 kg. The body is rotated in a vertical circular path of radius 0. 5 m. The body acquires a speed of 5 m s−1 at the bottom of the circular path. Strain produced in the string when the body is at the bottom of the circle is _____ ×10−5 . (Use Young's modulus 1011 N m−2 and g = 10 m s−2 )

Q24.Moment of Inertia (M.I.) of four bodies having same mass 𝑀 and radius 2𝑅 are as follows 𝐼1 = M.I. of solid sphere about its diameter 𝐼2 = M.I. of solid cylinder about its axis 𝐼3 = M.I. of solid circular disc about its diameter 𝐼4 = M.I. of thin circular ring about its diameter If 2𝐼2 + 𝐼3 + 𝐼4 = 𝑥𝐼1 then the value of 𝑥 will be _____ .

Q24.Two coils require 20 minutes and 60 minutes respectively to produce same amount of heat energy when connected separately to the same source. If they are connected in parallel arrangement to the same source; the time required to produce same amount of heat by the combination of coils, will be _____ min.

Q24.A geyser heats water flowing at a rate of 2. 0 kg per minute from 30°C to 70°C . If geyser operates on a gas burner, the rate of combustion of fuel will be _____ g min−1 . JEE Main 2022 (26 Jun Shift 2) JEE Main Previous Year Paper [Heat of combustion = 8 × 103 Jg−1 , Specific heat of water = 4. 2 Jg−1 ∘C−1 ]

Q24.As per given figures, two springs of spring constants 𝐾 and 2 K are connected to mass m. If the period of oscillation in figure (a) is 3 s, then the period of oscillation in figure (b) will be √𝑥 s. The value of 𝑥 is _____ .

Q24.A mass 0. 9 kg, attached to a horizontal spring, executes SHM with an amplitude A1 . When this mass passes through its mean position, then a smaller mass of 124 g is placed over it and both masses move together with amplitude A2 . If the ratio A2A1 is α−1α , then the value of α will be _____ .

Q24.The elastic behaviour of material for linear stress and linear strain, is shown in the figure. The energy density for a linear strain of 5 × 10−4 is _____ kJ m−3 . Assume that material is elastic upto the linear strain of 5 × 10−4 , JEE Main 2022 (26 Jun Shift 1) JEE Main Previous Year Paper

Q25.The metallic bob of simple pendulum has the relative density 5. The time period of this pendulum is 10 s. If the metallic bob is immersed in water, then the new time period becomes 5√𝑥 s. The value of 𝑥 will be _____ .

Q25.Two parallel plate capacitors of capacity C and 3C are connected in parallel combination and charged to a potential difference 18 V . The battery is then disconnected and the space between the plates of the capacitor of capacity C is completely filled with a material of dielectric constant 9 . The final potential difference across the combination of capacitors will be _____ V .

Q25.The frequency of echo will be _____ Hz if the train blowing a whistle of frequency 320 Hz is moving with a velocity of 36 km h-1 towards a hill from which an echo is heard by the train driver. Velocity of sound in air JEE Main 2022 (28 Jul Shift 1) JEE Main Previous Year Paper is 330 m s-1.

Q25.A wire of length 30 cm, stretched between rigid supports, has it's nth and (n + 1)th harmonics at 400 Hz and 450 Hz, respectively. If tension in the string is 2700 N , it's linear mass density is _____ kg m−1 .

Q25.A 1 m long copper wire carries a current of 1 A . If the cross section of the wire is 2. 0 mm2 and the resistivity of copper is 1. 7 × 10−8 Ω m. The force experienced by moving electron in the wire is _____ ×10−23 N (Charge of electron = 1. 6 × 10−19C )

Q25.The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is 31. 4 cm. The diameter of wire is measured as 2. 4 cm. The resistivity of the given wire is measured as x × 10−3 Ω cm. The value of x is _____ . [Take π = 3. 14 ]

Q25.Two resistors are connected in series across a battery as shown in figure. If a voltmeter of resistance 2000 Ω is used to measure the potential difference across 500 Ω resister, the reading of the voltmeter will be _____ V

Q25.A parallel plate capacitor is made up of stair like structure with a plate area A of each stair and that is x ε0 A , The connected with a wire of length b, as shown in the figure. The capacitance of the arrangement is b 15 value of x is _____ .

Q25.An ideal fluid of density 800 kg m−3 , flows smoothly through a bent pipe (as shown in figure) that tapers in cross-sectional area from a to a . The pressure difference between the wide and narrow sections of pipe is 2 4100 Pa . At wider section, the velocity of fluid is √x6 m s−1 for x = _____ . (Given g = 10 m s−2 )

Q25.A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine takes 300 J heat from the hot reservoir and delivers 180 J heat to the cold reservoir per cycle, is _____ K .

Q25.A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be

Q25.A composite parallel plate capacitor is made up of two different dielectric materials with different thickness ( t1 and t2 ) as shown in figure. The two different dielectric material are separated by a conducting foil F . The voltage of the conducting foil is _____ V .

Q25.At a certain temperature, the degrees of freedom per molecule for gas is 8 . The gas performs 150 J of work when it expands under constant pressure. The amount of heat absorbed by the gas will be _____ J.

Q25.A steam engine intakes 50 g of steam at 100°C per minute and cools it down to 20°C. If latent heat of vaporization of steam is 540 cal g-1, then the heat rejected by the steam engine per minute is _____ × 103 cal (Given : specific heat capacity of water : 1 cal g-1∘C-1)

Q25.Three point charges of magnitude 5 𝜇C, 0 . 16 𝜇C and 0 . 3 𝜇C are located at the vertices 𝐴, 𝐵, 𝐶 of a right angled triangle whose sides are 𝐴𝐵= 3 cm, 𝐵𝐶= 3√2 cm and 𝐶𝐴= 3 cm and point 𝐴 is the right angle corner. Charge at point 𝐴 experiences _____ N of electrostatic force due to the other two charges.

Q25.A potentiometer wire of length 10 m and resistance 20 Ω is connected in series with a 25 V battery and an external resistance 30 Ω. A cell of emf E in secondary circuit is balanced by 250 cm long potentiometer wire. The value of E (in volt) is x . The value of x is _____ . 10 JEE Main 2022 (24 Jun Shift 2) JEE Main Previous Year Paper

Q26.The speed of a transverse wave passing through a string of length 50 cm and mass 10 g is 60 m s-1. The area of cross-section of the wire is 2 . 0 mm2 and its Young's modulus is 1 . 2 × 1011 N m-2. The extension of the wire over its natural length due to its tension will be x × 10-5 m. The value of 𝑥 is _____ .

Q26.A circular coil of 1000 turns each with area 1 m2 is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of 0. 07 T. The maximum voltage generation will be _____ V.