Q. 22

# Figure shows an electrolyte of AgCl through which a current is passed. It is observed that 2.68 g of silver is deposited in 10 minutes on the cathode. Find the heat developed in the 20Ω resistor during this period. Atomic weight of silver is 107.9 g mol^{–1}.

Answer :

Given:

Mass of silver deposited, *m* = 2.68 g

Time, *t* = 10 minutes = 600 s

Using the formula, from faraday’s law of electrolysis –

where,

m = the mass of the substance deposited on the electrode

z=electrochemical equivalence

i=current passing

t=time taken

Now, heat developed in the 20 Ω resistor from Joule’s heating effect,

Where

I is the current in the circuit

R is the resistance of the resistor

T is the time period for which the current is allowed to flow through the circuit

Putting the above values in the formula, we get

Rate this question :

An electric bulb marked 220 V, 100 W will get fused if it is made to consume 150 W or more. What voltage fluctuation will the bulb withstand?

HC Verma - Concepts of Physics Part 2A servo voltage stabilizer restricts the voltage output to 220 V ± 1%. If an electric bulb rated at 220 V, 100 W is connected to it, what will be the minimum and maximum power consumed by it?

HC Verma - Concepts of Physics Part 2Figure shows an electrolyte of AgCl through which a current is passed. It is observed that 2.68 g of silver is deposited in 10 minutes on the cathode. Find the heat developed in the 20Ω resistor during this period. Atomic weight of silver is 107.9 g mol^{–1}.

HC Verma - Concepts of Physics Part 2

Find the charge required to flow through an electrolyte to liberate one atom of (a) a monovalent material and (b) a divalent material.

HC Verma - Concepts of Physics Part 2Find the thermo-emf developed in a copper-silver thermocouple when the junctions are kept at 0°C and 40°C. Use the data in table (33.1).

HC Verma - Concepts of Physics Part 2An immersion heater rated 1000 W, 220 V is used to heat 0.01 m^{3} of water. Assuming that the power is supplied at 220 V and 60% of the power supplied is used to heat the water, how long will it take to increase the temperature of the water from 15°C to 40°C?

An electric bulb, when connected across a power supply of 220 W, consumes a power of 60 W. If the supply drops to 180 V, what will be the power consumed? If the supply is suddenly increased to 240 V, what will be the power consumed?

HC Verma - Concepts of Physics Part 2A coil of resistance 100 Ω is connected across a battery of emf 6.0V. Assume that the heat developed in the coil is used to raise its temperature. If the heat capacity of the coil is 4.0 J K^{–1}, how long will it take to raise the temperature of the coil by 15°C.

When a current passes through a resistor, its temperature

increases. Is it an adiabatic process?

HC Verma - Concepts of Physics Part 2