Physics

A 10 Ω resistance is connected across 220 V - 50Hz AC supply. The time taken by the current to change from its maximum value to the rms value is :

Two ideal electric dipoles A and B, having their dipole moment p₁ and p₂ respectively are placed on a plane with their centres at O as shown in the figure. At point C on the axis of dipole A, the resultant electric field is making an angle of 37° with the axis. The ratio of the dipole moment of A and B, p₁ and p₂ , is:
(take sin 37° = 3/5)

Two vectors X and Y have equal magnitude. The magnitude of (X - Y) is n times the magnitude of (X + Y). The angle between X and Y is :

An electron moving with speed v and a photon moving with speed c, have same D-Broglie wavelength. The ratio of kinetic energy of electron to that of photon is :

Water droplets are coming from an open tap at a particular rate. The spacing between a droplet observed at 4? second after its fall to the next droplet is 34.3 m. At what rate the droplets are coming from the tap? (Take g = 9.8 m/s²)

A balloon was moving upwards with a uniform velocity of 10 m/s. An object of finite mass is dropped from the balloon when it was at a height of 75 m from the ground level. The height of the balloon from the ground when object strikes the ground was around :
(takes the value of g as 10 m/s²)

In the given potentiometer circuit arrangement, the balancing length AC is measured to be 250 cm. When the galvanometer connection is shifted from point (1) to point (2) in the given diagram, the balancing length becomes 400 cm. The ratio of the emf of two cells, ε₁/ε₂,, is:

A ray of light entering from air into a denser medium of refractive index 4/3, as shown in figure. The light ray suffers total internal reflection at the adjacent surface as shown. The maximum value of angle θ should be equal to :

What should be the order of arrangement of de-Broglie wavelength of electron (λ?), an α – particle (λα) and proton (λ?) given that all have the same kinetic energy ?

A ray of laser of a wavelength 630 nm is incident at an angle of 30° at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is 2.42 and that of air is 1. Choose the correct option.