Class 12th

A radioactive β –emission. A detector records n β –particles in 2s and by next 2s (accumulatively) it records 1.1 n β –particle. Number of β –particles recorded by detector after a long time, is

The reagent, from the following, which converts benzoic acid to benzaldehyde in one step is

Halogenation of which one of the following will yield m-substituted product with respect to methyl group as a major product?

A ray of light is incident on a slab as shown in figure. The refractive index of medium of slab changes as μ = √(1 + y²). The angle made by ray with x – axis at y = √2 is

Two conducting circular loops of radii R₁ and R₂ are placed in the same plane with their centres coinciding. If R₁ » R₂, the mutual inductance M between them will be directly proportional to:

An equi-concave lens of radius of curvature 15 cm and μ = 1.5 is placed in water (μ = 1.33). If one surface is silvered, then image distance from lens when an object is placed at distance of 14 cm from the lens is

A rod of length l slides against the perpendicular wall, such that the lowest point (A) of the rod slides with a speed v on horizontal surface as shown in figure. There exist a uniform magnetic field throughout the region. Now, what is the distance of point 'P' on the rod from end 'A' such that, the induced emf across 'P' and 'A' is maximum?

A simple LR circuit is connected to a battery at t = 0. The time instant at which rate of energy storage in inductor is half of power delivered by battery

Twenty seven drops of same size are charged at 220 V each. They combine to form a bigger drop. Calculate the potential of the bigger drop.