JEE Main entrance exam Question Bank Solutions for Physics (JEE Main)

Wein's constant is 2892 × 10^-6 SI unit and the value of λm for moon is 14.46 micron. The surface temperature of moon is ______.

The aperture of the objective is 24.4 cm. The resolving power of this telescope. If a light of wavelength 2440 Å is used to see the object will be ______.

Wavelength of light used in an optical instrument are λ₁ = 4000 Å and λ₂ = 5000 Å, then ratio of their respective resolving powers (corresponding to λ₁ and λ₂) is ______.

Which of the following is closer to a black body?

According to Newton's law of cooling, the rate of cooling of the body is proportional to (Δθ), where Δθ is the difference between the temperature of the body and the surroundings, and n is equal to ______.

In 5 minutes, a body cools from 75°C to 65°C at a room temperature of 25°C. The temperature of the body at the end of the next 5 minutes is ______°C.

Water from a pipe is coming at a rate of 100 liters per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of ______.

(density of water = 1000 kg/m³, coefficient of viscosity of water = 1 mPa s)

If p is the density and η is the coefficient of viscosity of fluid that flows with a speed v in the pipe of diameter d, the correct formula for Reynolds number R_e is ______.

A wire fixed at the upper end stretches by length l by applying a force F. The work done in stretching is ______.

A small spherical ball of radius 0.1 mm and density 10⁴ kg m^-3 falls freely under gravity through a distance of h before entering a tank of water. If, after entering the water the velocity of the ball does not change and it continues to fall with the same constant velocity inside the water, then the value of h will be ______ m.

(Given g = 10 ms^-2, the viscosity of water = 1.0 × 10^-5 N-sm^-2).

Two solid spherical balls of radius r₁ and r₂ (r₂ < r₁), of density σ are tied up with a long string and released in a viscous liquid column of lesser density ρ and coefficient of viscosity η, with the string just taut as shown. The terminal velocity of spheres is ______.

If ‘M’ is the mass of water that rises in a capillary tube of radius ‘r’, then the mass of water which will rise in a capillary tube of radius ‘2r’ is ______.

Figure shows the vertical cross-section of a vessel filled with liquid of density ρ. The normal thrust per unit area on the walls of the vessel at point P, as shown will be:

A wooden object floats in water kept in a beaker. The object is near a side of the beaker. Let P₁, P₂, P₃ be the pressures at the three points A, B and C of bottom as shown in the figure.

A large tank is filled with water (density = 10³kg/m³). A small hole is made at a depth 10 m below water surface. The range of water effluxing out of the hole is R on ground. The extra pressure (in atm) must be applied on the water surface so that the range becomes 2R is ______. (Take 1 atm = 10⁵ Pa and g = 10 m/s²)

An ideal fluid is flowing in two pipes of same cross-sectional pipes area. Both the pipes are connected with two vertical tubes, of length h₁ and h₂ as shown in figure. The flow is stream line in both pipes. If velocity of fluid at A, B, and C are 2 m/s, 4 m/s and 4 m/s respectively, the velocity of fluid at D (in m/s) is ______.

An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipes are 6.4 cm and 4.8 cm, respectively. The ratio of the minimum and the maximum velocities of fluid in this pipe is ______.

A solid metallic cube having a total surface area of 24 m² is uniformly heated. If its temperature is increased by 10°C, calculate the increase in the volume of the cube.

(Given: α = 5.0 × 10^-4°C^-1)