Current Electri...

An ammeter, suspected to give inaccurate reading, is connected in series with a silver voltameter. The ammeter indicates 0.54 A. A steady current passed for one hour deposits 2.0124 g of silver. If the E.C.E. of silver is 1.118 × 10^–3 g/C^–1, then the error in ammeter reading is

If 1 A of current is passed through CuSO₄ solution for 10 seconds, then the number of copper ions deposited at the cathode will be about

Incandescent bulbs are designed by keeping in mind that the resistance of their filament increases with increase in temperature. If at room temperature, 100 W, 60 W and 40 W bulbs have filament resistances R₁₀₀, R₆₀ and R₄₀ respectively, the relation between these resistances is

A thermocouple of resistance 1.6 Ω is connected in series with a galvanometer of 8Ω resistance. The thermocouple develops an e.m.f. of 10 µV per degree temperature difference between two junctions. When one junction is kept at 0° C and the other in a molten metal, the galvanometer reads 8 millivolt. The temperature of molten metal, when e.m.f. varies linearly with temperature difference, will be

The emf of a thermocouple, one junction of which is kept at 0°C, is given by e = at + bt². The Peltier co-efficient will be

A coil of wire of resistance 50 Ω is embedded in a block of ice. If a potential difference of 210 V is applied across the coil, the amount of ice melted per second will be

The same mass of copper is drawn into two wires 1 mm and 2 mm thick. Two wires are connected in series and current is passed through them. Heat produced in the wire is in the ratio

The temperature of hot junction of a thermo-couple changes from 80° C to 100° C. The percentage change in thermoelectric power is

A thermocouple uses Bismuth and Tellurium as the dissimilar metals. The sensitivity of bismuth is –72g µV/°C and that of the tellurium is 500 µV/°C. If the difference between hot and cold junction is 100°C, then the maximum output will be

Three wires of copper, iron and nickel are joined to form three junctions as shown in Fig. When the temperature of junction 1 is kept 50° C with the other two junctions at 0°C, the sensitive galvanometer gives a deflection of 14 divisions. When the temperature of junction 3 is kept 50° C, with the other two junctions at 0°C, the galvanometer gives a deflection of 11 divisions. Then the deflection given by the galvanometer, when temperature of the junction 2 is kept at 50°C, with the other two junctions at 0° C, will be