Electricity and its effects: Electric intensity, potential, potential difference, electric current, Ohm's law, resistance, specific resistance, factors influencing resistance, combination of resistance (numerical examples), thermal effect of current and its use, calculation of power and electrical energy spent (numerical), precautions in electric experiments

The equivalent resistance of the following network shown in figure between the points A and B is

The resistance of a wire does not depend on

What is the SI unit of current density?

The total resistance of three resistances connected in parallel is

What is the peak value of an alternating current that produces three times the heat per second as a direct current of 2.0 A in a resistance R?

A battery of e.m.f. 1.5 V has a terminal potential difference of 1.25 V when an external resistance of 25 Ω is connected to it. The internal resistance of the battery will be

Two positive point charges of 12 $\mu$ C and 8 $\mu$ C (micro coulomb) respectively are 10 cm apart. The work done in bringing them 4 cm closer so that they are 6 cm apart is
(1 / (4 $\pi$\varepsilon_0) = $9 * 10^9$ mF^-1)

An electric toaster uses nichrome for its heating element when a negligibly small current passes through it, its resistance at room temperature 25°C is found to be 75 Ω. When the toaster is connected to a 230 V supply, a steady state current of 2.3 A flows. The steady state temperature of the nichrome element will be (Take temperature co-efficient of resistance of nichrome 1.7 × 10⁻⁴ °C⁻¹.)

At the time of short circuit, the amount of current in the circuit :

Which of the following statements is true regarding the specific resistance of a wire?

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If equivalent resistance is R' then the ratio of R/R' is

The amount of heat produced in 5 minutes by an electric heater rated at 1000 W is

If an electric current is passed through a nerve, the human :

Which of the following instrument can detect the presence of electric current in a circuit ?

The surface of a spherical shell is uniformly charged. Then what is the electric field inside the spherical shell: