Practice Questions

Q23.There is an air bubble of radius 1. 0 mm in a liquid of surface tension 0. 075 N m–1 and density 1000 kg m–3 at a depth of 10 cm below the free surface. The amount by which the pressure inside the bubble is greater than the atmospheric pressure is _______ Pa(g = 10 m s−2).

Q23.Two wires each of radius 0 . 2 cm and negligible mass, one made of steel and the other made of brass are loaded as shown in the figure. The elongation of the steel wire is ______10 – 6 m. [Young's modulus for steel = 2 × 1011 N m – 2 and 𝑔= 10 m s – 2] JEE Main 2023 (10 Apr Shift 1) JEE Main Previous Year Paper

Q23.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology. Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar) In the light of given 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 but R is NOT 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 the correct explanation of A

Q23.Given below are two statements : Statement I : Electromagnetic waves are not deflected by electric and magnetic field. Statement II : The amplitude of electric field and the magnetic field in electromagnetic waves are related to . each other as E0 = √μ0ε0 B0 In the light of the above statements, choose the correct answer from the options given below: (1) Statement I is true but statement II is false (2) Both Statement I and Statement II are true (3) Statement I is false but statement II is true (4) Both Statement I and Statement II are false

Q23.A thin prism P1 with an angle 6° and made of glass of refractive index 1. 54 is combined with another prism P2 made from glass of refractive index 1. 72 to produce dispersion without average deviation. The angle of prism P2 is : (1) 6° (2) 1. 3° (3) 7. 8° (4) 4. 5°

Q23.A certain pressure '𝑃' is applied to 1 litre of water and 2 litre of a liquid separately. Water gets compressed to 0 . 01% whereas the liquid gets compressed to 0 . 03%. The ratio of Bulk modulus of water to that of the liquid 3 is 𝑥. The value of 𝑥 is ______.

Q23.Two plates A and B have thermal conductivities 84 W m-1 K-1 and 126 W m-1 K-1 respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If the temperatures of the outer surfaces of A and B are kept at 100∘C and 0∘C respectively, then the temperature of the surface of contact in steady state is_____ ∘C.

Q23.In a Young’s double slit experiment, two slits are illuminated with a light of wavelength 800 nm . The line joining A1P is perpendicular to A1A2 as shown in the figure. If the first minimum is detected at P , the value of slits separation a will be : JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper The distance of screen from slits D = 5 cm . (1) 0. 4 mm (2) 0. 5 mm (3) 0. 2 mm (4) 0. 1 mm

Q23.Solid sphere 𝐴 is rotating about an axis 𝑃𝑄. If the radius of the sphere is 5 cm, then its radius of gyration about 𝑃𝑄 will be √𝑥 cm. The value of 𝑥 is _____.

Q23.A coil has an inductance of 2 H and resistance of 4 Ω. A 10 V is applied across the coil. The energy stored in the magnetic field after the current has built up to its equilibrium value will be _____ ×10−2 J

Q23.A solid sphere of mass 500 g radius 5 cm is rotated about one of its diameter with angular speed of 10 rad s-1. If the moment of inertia of the sphere about its tangent is 𝑥× 10-2 times its angular momentum about the diameter. Then the value of 𝑥 will be

Q23.Two identical solid spheres each of mass 2 kg and radii 10 cm are fixed at the ends of a light rod. The separation between the centres of the spheres is 40 cm . The moment of inertia of the system about an axis perpendicular to the rod passing through its middle point is______ × 10 – 3 kg m2 .

Q24.The length of a wire becomes 𝑙1 and 𝑙2 when 100 N and 120 N tension are applied respectively. If 1 10𝑙2 = 11𝑙1, then the natural length of wire will be 𝑥𝑙1. Here the value of 𝑥 is 𝜋

Q24.Two transparent media having refractive indices 1. 0 and 1. 5 are separated by a spherical refracting surface of radius of curvature 30 cm. The centre of curvature of surface is towards denser medium and a point object is placed on the principal axis in rarer medium at a distance of 15 cm from the pole of the surface. The distance of image from the pole of the surface is cm.

Q24.A thin rod having a length of 1 m and area of cross-section 3 × 10-6 m2 is suspended vertically from one end. The rod is cooled from 210°C to 160°C. After cooling, a mass 𝑀 is attached at the lower end of the rod such that the length of rod again becomes 1 m. Young's modulus and coefficient of linear expansion of the rod are 2 × 1011 N m-2 and 2 × 10-5 K-1, respectively. The value of 𝑀 is ______ kg. (Take 𝑔= 10 m s-2 )

Q24.A capacitor of capacitance 900 µ F is charged by a 100 V battery. The capacitor is disconnected from the battery and connected to another uncharged identical capacitor such that one plate of uncharged capacitor connected to positive plate and another plate of uncharged capacitor connected to negative plate of the charged capacitor. The loss of energy in this process is measured as 𝑥× 10-2 J. The value of 𝑥 is ______.

Q24.A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index 5 is poured 3 inside the bucket, then microscope have to be raised by 30 cm to focus the object again. The height of the liquid in the bucket is : (1) 75 cm (2) 50 cm (3) 18 cm (4) 12 cm

Q24.A fish rising vertically upward with a uniform velocity of 8 m s–1, observes that a bird is diving vertically downward towards the fish with the velocity of 12 m s–1. If the refractive index of water is 34 , then the actual velocity of the diving bird to pick the fish, will be __________m s−1.

Q24.A plane electromagnetic wave of frequency 20 MHz propagates in free space along x-direction. At a particular → → space and time E = 6. 6ˆj V m−1 . What is B at this point? (1) 2. 2 × 10−8ˆkT (2) −2. 2 × 10−8ˆiT (3) −2. 2 × 10−8ˆkT (4) 2. 2 × 10−8ˆi T

Q24.A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should. (Select the best option) (1) Increase the wave length of the light (2) Increase the refractive index of the medium between the object and objective lens (3) Decrease the focal length of the eye piece (4) Decrease the diameter of the objective lens

Q24.In a Young’s double slit experiment, the intensities at two points, for the path difference λ and λ ( λ being the 4 3 wavelength of light used) are I1 and I2 respectively. If I0 denotes the intensity produced by each one of the individual slits, then I1+I2 = ______ . I0

Q24.A ray of light is incident from air on a glass plate having thickness √3 cm and refractive index √2 . The angle of incidence of a ray is equal to the critical angle for glass-air interface. The lateral displacement of the ray when it passes through the plate is ____ × 10−2 cm . (given sin 15°= 0. 26 )

Q24.Two objects A and B are placed at 15 cm and 25 cm from the pole in front of a concave mirror having radius of curvature 40 cm . The distance between images formed by the mirror is: (1) 40 cm (2) 60 cm (3) 160 cm (4) 100 cm

Q24.The fundamental frequency of vibration of a string between two rigid support is 50 Hz. The mass of the string is 18 g and its linear mass density is 20 g m−1 . The speed of the transverse waves so produced in the string is _______ m s–1 .

Q24.In an experiment with sonometer when a mass of 180 g is attached to the string, it vibrates with fundamental frequency of 30 Hz. When a mass 𝑚 is attached, the string vibrates with fundamental frequency of 50 Hz. The value of 𝑚 is ______ g.