Practice Questions

Q25.Consider two identical springs each of spring constant k and negligible mass compared to the mass M as shown. Fig. 1 shows one of them and Fig. 2 shows their series combination. The ratios of time period of oscillation of the two SHM is Tb = √x, where value of x is ______. Ta (Round off to the Nearest Integer)

Q25.A particle executes simple harmonic motion represented by displacement function as x(t) = A sin(ωt + ϕ). If the position and velocity of the particle at t = 0 s are 2 cm and 2ω cm s−1 respectively, then its amplitude is x√2 cm where the value of x is

Q25.In the figure given, the electric current flowing through the 5 kΩ resistor is x mA . The value of x to the nearest integer is ________.

Q25.Two separate wires A and B are stretched by 2 mm and 4 mm respectively, when they are subjected to a force of 2 N. Assume that both the wires are made up of same material and the radius of wire B is 4 times that of the radius of wire A. The length of the wires A and B are in the ratio of a : b. Then ab can be expressed as x1 , where x is _____.

Q25.The electric field intensity is produced by the radiation coming from a 100 W bulb at a distance of 3 m is E . E . Where The electric field intensity produced by the radiation coming from 60 W at the same distance is √x5 the value of x =_________ . → 2 3 with E0 = 4. 0 × 103 N C−1. The flux of this

Q25.A prism of refractive index n1 and another prism of refractive index n2 are stuck together (as shown in the figure). n1 and n2 depend on λ, the wavelength of light, according to the relation n1 = 1. 2 + 10.8×10−14λ2 and 1.8×10−14 n2 = 1. 45 + λ2 The wavelength for which rays incident at any angle on the interface BC pass through without bending at that interface will be ____ nm.

Q25.If one wants to remove all the mass of the earth to infinity in order to break it up completely. The amount of GM energy that needs to be supplied will be x 2 where x is ________. R 5 (Round off to the Nearest Integer) ( M is the mass of earth, R is the radius of earth, G is the gravitational constant)

Q25.In the reported figure, heat energy absorbed by a system in going through a cyclic process is ______ πJ. JEE Main 2021 (20 Jul Shift 1) JEE Main Previous Year Paper

Q25.The area of cross-section of a railway track is 0. 01 m2. The temperature variation is 10 °C. Coefficient of linear expansion of material of track is 10−5 ∘C−1. The energy stored per meter in the track is J m−1. (Young's modulus of material of track is 1011 N m−2 )

Q25.A wire having a linear mass density 9. 0 × 10−4 kg m−1 is stretched between two rigid supports with a tension of 900 N. The wire resonates at a frequency of 500 Hz. The next higher frequency at which the same wire resonates is 550 Hz. The length of the wire is ___________ m.

Q25.The electric field in a region is given by E = ( 5 E0ˆi + 5 E0ˆj) through the rectangular surface of area 0. 2 m2 (parallel to y −z plane) to that of the surface of area 0. 3 m2 (parallel to x −z plane) is a : b = a : 2, where a =? [Here ˆi, ˆj and ˆk are unit vectors along x, y and z -axes respectively] Q26. 512 identical drops of mercury are charged to a potential of 2 V each. The drops are joined to form a single drop. The potential of this drop is V in Volt.

Q25.The width of one of the two slits in a Young's double slit experiment is three times the other slit. If the amplitude of the light coming from a slit is proportional to the slit-width, the ratio of minimum to maximum intensity in the interference pattern is 𝑥: 4 where 𝑥 is _______ .

Q25.Time period of a simple pendulum is T . The time taken to complete 5 oscillations starting from mean position 8 is α T . The value of α is ______ . 12 JEE Main 2021 (26 Feb Shift 2) JEE Main Previous Year Paper Q26. 27 similar drops of mercury are maintained at 10 V each. All these spherical drops combine into a single big drop. The potential energy of the bigger drop is ___________ times that of a smaller drop.

Q25.Two cars are approaching each other at an equal speed of 7. 2 km hr−1. When they see each other, both blow horns having a frequency of 676 Hz. The beat frequency heard by each driver will be _______ Hz. [Velocity of sound in air is 340 m s−1.

Q26.Four identical rectangular plates with length, l = 2 cm and breadth, b = 32 cm are arranged as shown in figure. The equivalent capacitance between A and C is xε0d . The value of x is _______. (Round off to the Nearest Integer)

Q26.An electric bulb rated as 200 W at 100 V is used in a circuit having 200 V supply. The resistance 𝑅 that must be put in series with the bulb so that the bulb delivers the same power is ______ Ω.

Q26.First, a set of n equal resistors of 10 Ω each are connected in series to a battery of E.M.F. 20 V and internal resistance 10 Ω. A current I is observed to flow. Then, the n resistors are connected in parallel to the same battery. It is observed that the current is increased 20 times, then the value of n is ___________.

Q26.For the circuit shown, the value of current at time t = 3. 2 s will be ______ A . JEE Main 2021 (27 Jul Shift 2) JEE Main Previous Year Paper [Voltage distribution V(t) is shown by Fig. (1) and the circuit is shown in Fig. (2)]

Q26.A coil in the shape of an equilateral triangle of side 10 cm lies in a vertical plane between the pole pieces of permanent magnet producing a horizontal magnetic field 20 mT. The torque acting on the coil when a current of 0. 2 A is passed through it and its plane becomes parallel to the magnetic field will be √x × 10−5 Nm . The value of x is

Q26.A particle performs simple harmonic motion with a period of 2 second. The time taken by the particle to cover a displacement equal to half of its amplitude from the mean position is 1 s. The value of a to the nearest a integer is

Q26.A particle of mass 9. 1 × 10−31 kg travels in a medium with a speed of 106 m s−1 and a photon of radiation of linear momentum 10−27 kg m s−1 travels in a vacuum. The wavelength of the photon is ____ times the wavelength of the particle. ∘

Q26.A point charge of +12 μC is at a distance 6 cm vertically above the centre of a square of side 12 cm as shown in figure. The magnitude of the electric flux through the square will be _______ ×103 N m2 C−1. JEE Main 2021 (24 Feb Shift 2) JEE Main Previous Year Paper

Q26.A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which R = 8 Ω, L = 24 mH and C = 60 μF. The value of power dissipated at resonant condition is x kW . The value of x to the nearest integer is _______.

Q26.A capacitor of 50μF is connected in a circuit as shown in figure. The charge on the upper plate of the capacitor is _________ μC.

Q26.A source and a detector move away from each other in absence of wind with a speed of 20 m s−1 , with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of source considering the speed of sound in the air 340 m s−1 will be _____ Hz .