Practice Questions

Q10.A steel rod of length 1 m and cross-sectional area 10−4 m2 is heated from 0°C to 200°C without being allowed to extend or bend. The compressive tension produced in the rod is _____ ×104 N . (Given Young's modulus of steel = 2 × 1011 N m−2 , coefficient of linear expansion = 10−5 K−1 )

Q10.Glycerin of density 1. 25 × 103 kg m–3 is flowing through the conical section of pipe. The area of cross- section of the pipe at its ends are 10 cm2 and 5 cm2 and pressure drop across its length is 3 N m–2 . The rate of flow of glycerine through the pipe is x × 10–5 m3 s–1 . The value of x is _____.

Q10.The electric field in an electromagnetic wave is given as →𝐸= 20sin𝜔𝑡- 𝑥 →jN C-1, where 𝜔 and 𝑐 are angular frequency and velocity of electromagnetic wave 𝑐 respectively. The energy contained in a volume of 5 × 10-4 m3 will be (Given 𝜀0 = 8 . 85 × 10-12C2 N-1 m-2) (1) 88 . 5 × 10-13 J (2) 17 . 7 × 10-13 J (3) 28 . 5 × 10-13 J (4) 8 . 85 × 10-13 J

Q10.A body cools from 60°C to 40°C in 6 minutes. If, temperature of surroundings is 10°C . Then, after the next 6 minutes, its temperature will be ______ °C.

Q10.A water heater of power 2000 W is used to heat water. The specific heat capacity of water is 4200 J kg−1 K−1 . The efficiency of heater is 70%. Time required to heat 2 kg of water from 10°C to 60°C is _____ s . (Assume that the specific heat capacity of water remains constant over the temperature range of the water).

Q10.The maximum potential energy of a block executing simple harmonic motion is 25 J. A is amplitude of 𝐴 oscillation. At 2, the kinetic energy of the block is (1) 37 . 5 J (2) 9 . 75 J (3) 18 . 75 J (4) 12 . 5 J

Q10.As shown in the figure, in an experiment to determine Young's modulus of a wire, the extension-load curve is plotted. The curve is a straight line passing through the origin and makes an angle of 45° with the load axis. The length of wire is 62. 8 cm and its diameter is 4 mm. The Young's modulus is found to be x × 104 N m−2 The value of x is _______.

Q10.The surface tension of soap solution is 3. 5 × 10−2 N m−1 . The amount of work done required to increase the radius of soap bubble from 10 cm to 20 cm is _____ ×10−4 J . (take π = 227 )

Q10.The elastic potential energy stored in a steel wire of length 20 m stretched through 2 cm is 80 J. The cross sectional area of the wire is _____ mm2. (Given, Y = 2. 0 × 1011 N m–2 )

Q10.A particle executes SHM of amplitude 𝐴. The distance from the mean position when its kinetic energy becomes equal to its potential energy is: (1) 1 (2) 2𝐴 √2𝐴 (3) √2𝐴 (4) 12𝐴

Q10.An aluminium rod with Young’s modulus Y = 7. 0 × 1010 N m−2 undergoes elastic strain of 0. 04%. The energy per unit volume stored in the rod in SI unit JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper (1) 2800 (2) 11200 (3) 5600 (4) 8400

Q10.A spherical drop of liquid splits into 1000 identical spherical drops. If ui is the surface energy of the original = ( 10x ). Then drop and uf is the total surface energy of the resulting drops, the (ignoring evaporation), ufui value of x is ______:

Q10.In a linear Simple Harmonic Motion (SHM) (A) Restoring force is directly proportional to the displacement. (B) The acceleration and displacement are opposite in direction. (C) The velocity is maximum at mean position. (D) The acceleration is minimum at extreme points. Choose the correct answer from the options given below: (1) (C) and (D) only (2) (A), (C) and (D) only (3) (A), (B) and (C) only (4) (A), (B) and (D) only

Q10.A faulty thermometer reads 5°C in melting ice and 95°C in steam. The correct temperature on absolute scale will be ______ K when the faulty thermometer reads 41°C.

Q10.A particle executes S.H.M. of amplitude 𝐴 along 𝑥-axis. At 𝑡= 0, the position of the particle is 𝑥= and it 2 moves along positive 𝑥-axis. The displacement of particle in time 𝑡 is 𝑥= 𝐴 sin𝜔𝑡 + 𝛿, then the value 𝛿 will be (1) 𝜋 (2) 𝜋 2 6 𝜋 𝜋 (3) (4) 3 4

Q10.The pressure ( 𝑃) and temperature ( 𝑇) relationship of an ideal gas obeys the equation 𝑃𝑇2 = constant. The volume expansion coefficient of the gas will be : 3 (1) 3𝑇2 (2) 𝑇2 3 3 (3) (4) 𝑇3 𝑇

Q10.The distance between two plates of a capacitor is 𝑑 and its capacitance is 𝐶1, when air is the medium between 2𝑑 the plates. If a metal sheet of thickness and of the same area as plate is introduced between the plates, the 3 𝐶2 capacitance of the capacitor becomes 𝐶2 . The ratio is 𝐶1 (1) 3 : 1 (2) 2 : 1 (3) 4 : 1 (4) 1 : 1

Q11.A parallel plate capacitor of capacitance 2 F is charged to a potential 𝑉. The energy stored in the capacitor is 𝐸1. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The 𝐸2 energy stored in the combination is 𝐸2. The ratio is 𝐸1 (1) 2: 1 (2) 2: 3 (3) 1: 2 (4) 1: 4

Q11.A body cools in 7 minutes from 60oC to 40oC. The temperature of the surrounding is 10oC. The temperature of the body after the next 7 minutes will be (1) 30oC (2) 32oC (3) 34oC (4) 28oC

Q11.The surface of water in a water tank of cross section area 750 cm2 on the top of a house is h m. above the tap level. The speed of water coming out through the tap of cross section area 500 mm2 is 30 cm s−1 . At that instant, dh is x × 10−3 m s−1 . The value of x will be ______. dt

Q11.A metal block of base area 0. 20 m2 is placed on a table, as shown in figure. A liquid film of thickness 0. 25 mm is inserted between the block and the table. The block is pushed by a horizontal force of 0. 1 N and moves with a constant speed. If the viscosity of the liquid is 5. 0 × 10–3 Pl, the speed of block is ______ ×10−3 m s−1 .

Q11.Let 𝜎 be the uniform surface charge density of two infinite thin plane sheets shown in figure. Then the electric fields in three different region 𝐸𝐼 , 𝐸𝐼𝐼 and 𝐸𝐼𝐼𝐼 (1) → 𝐸𝐼= 2𝜎 ^𝑛, →𝐸𝐼𝐼= 0, →𝐸𝐼𝐼𝐼= 2𝜎 ^𝑛 (2) →𝐸𝐼= 0, →𝐸𝐼𝐼= 𝜎 ^𝑛, →𝐸𝐼𝐼𝐼= 0 ∈0 ∈0 ∈0 → 𝜎 → → 𝜎 → -𝜎 → → 𝜎 (3) ^𝑛 𝐸𝐼= ^𝑛, 𝐸𝐼𝐼= 0, 𝐸𝐼𝐼𝐼= 𝐸𝐼= 2 ∈0 ^𝑛, 𝐸𝐼𝐼= 0, 𝐸𝐼𝐼𝐼= 2 ∈0 ^𝑛 (4) ∈0 ∈0

Q11.Heat energy of 735 J is given to a diatomic gas allowing the gas to expand at constant pressure. Each gas molecule rotates around an internal axis but do not oscillate. The increase in the internal energy of the gas will be: (1) 525 J (2) 441 J (3) 572 J (4) 735 J

Q11.Work done by a Carnot engine operating between temperatures 127°C and 27°C is 2 kJ . The amount of heat transferred to the engine by the reservoir is: (1) 8 kJ (2) 2. 67 kJ (3) 2 kJ (4) 4 kJ

Q11.According to law of equipartition of energy the molar specific heat of a diatomic gas at constant volume where the molecule has one additional vibrational mode is :- (1) 9 R (2) 5 R 2 2 (3) 3 R (4) 7 R 2 2