MEDIUM
12th West Bengal Board
IMPORTANT
Earn 100

A calorimeter coil is immersed in a calorimeter of heat capacity 50JC-1 containing 1.0 kg of a liquid of specific heat capacity 450JKg-1C-1. The temperature of liquid rises by 10oC when 2.0 A current is passed for the 10 minutes. Find the resistance of the coil.

Important Questions on Thermal Effect and Chemical Effect of Current

HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 8
The temperature of water in a tap is 22°C. It is desired to draw a continuous supply of water at the temperature of the human body 98.6°F flowing at the rate of one litre per minute. How much power will be consumed by a heater coil placed in the path of the water? What will be the current flowing if the supply voltage is 210 V. Neglect the heat loss due to radiation.
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 9
In an electrical installation of a cinema hall there are forty 60 W lamps, sixty one 200 W lamps, eight 40 W lamps and twenty 1.5 H.P. electrical fans. Find the minimum horsepower of the dynamo that can maintain the supply and also the cost for the electrical energy for the month of April, if these are run on the average of 8hr. A day and the charge for one BOT is 25 paise.
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 10
A 5 H.P. electric motor working on 220 V mains runs for 8 hours a day. If electricity is rated Rs 2.40 a unit, find the cost of running it for 30 days. Also find the current through the motor when running on full capacity.
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 11
A certain quantity of water in an electric kettle begins to boil 15 min after the kettle is switched on. The heating element consists of a coil of wire 5 m long. By how much should the length of the heating element be increased or decreased in order that the same quantity of water in the kettle to boil 12 min after the kettle is switched on? Neglect heat loss to the surroundings. 
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 12
The burner of an electric stove is made up of three sections of equal resistances. If the three sections are connected in parallel water in a tea-kettle begins to boil in 6 minutes. When will the same mass of water in the tea kettle begins to boil if the sections are connected in series?
EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 13
In order for a 60 V,120 W lamp to work at its full when inserted in 220 V d.c. line, a resistor of what magnitude should be placed in series with it?
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 14
An electric kettle taking 3.5 A at 210 Vbrings 1200c.c. of water from 25°C to 95°C in 12 min. Find the percentage of energy supplied which goes towards heating water.
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 6 - Thermal Effect and Chemical Effect of Current>EXERCISE 6>Q 15
A constant current of 1A flows through a platinum wire of resistance 5 ohm stretched along the axis of a cylindrical tube through which a steady stream of water passes at a rate of 15cm3 per minute. The steady difference between the temperature of the water entering and leaving the tube is 4.8°C. Neglecting losses of heat, calculate the mechanical equivalent of heat.