Physics Current Electricity

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 current through a wire-depends on time as

i = a₀t + bt²

Where a₀ = 20A/s and b = 8As^-2. Find the charge crossed through a section of the wire in 15s.

A cell E₁ of emf 6V and internal resistance $2\Omega$ is connected with another cell E₂ of emf 4V and internal resistance $8\Omega$  (as shown in the figure). The potential difference across points X and Y is:

In connection with the circuit drawn below, the value of current flowing through 2 $k\Omega$ resistor is________ * 10^-4A

A wire of $1\Omega$  has a length of 1m. It is stretched till its length increases by 25%. The percentage change in resistance to the nearest integer is:

In an electrical circuit, a battery is connected to pass 20 C of charge through it in a certain given time. The potential difference between two plates of the battery is maintained at 15V. The work done by the battery is--------- J.

Five equal resistances are connected in a network as shown in figure. The net resistance between  the points A and B is

A cylindrical wire of radius 0.5mm and conductivity 5 * 10⁷ S/m is subjected to an electric field of 10m V/m. The expected value of current in the wire will be x³πmA. The value of x is………………….

In the given circuit of potentiometer, the potential difference E across AB (10m length) is larger than E₁ and E₂ as well. For key K₁ (closed), the jokey is adjusted to touch the wire at point J₁ so that there is no deflection in the galvanometer. Now the first battery (E₁) is replaced by second battery (E₂) for working by making K₁ open and K₂ closed. The galvanometer gives then null deflection at J₂. The value of   $\frac{E_1}{E_2}is\frac{a}{b},$ where a = …………….

A current of 6 A enters one corner P of an equilateral triangle PQR having 3 wires of resistance $2\Omega$  each and leaves by the corner R. The currents i₁ in ampere is………