14.1: A current of 3 mA is flowing through a wire for 1 minute. What is the charge flowing through the wire? Ans. (180 𝐱10⁻³ C)


14.2: At 100,000 Ω, how much current flows through your body if you touch the terminals of a 12 V battery? If your skin is wet, so that your resistance is only 1000 Ω, how much current would you receive from the same battery? Ans.(1.2 𝐱 10⁻⁴ A, 1.2 𝐱 10⁻² A)

14.3 : The resistance of a conductor wire is 10 MΩ. If a potential difference of 100 volt is applied across its ends, then find the value of current passing through it in mA. Ans. ( 0.01 mA)


14.4: By applying a potential difference of 10 V across a conductor a current of 1.5 A passes through it. How much energy would be obtained from the current in 2 minutes? Ans.(1800 J)


14.5: Two resistances of 2 kΩ and 8 kΩ are joined in series, if a 10 V battery is connected acr oss the ends of this combination, find the following quantities:
(a) The equivalent resistance of the series combination. 
(b) Current passing through each of the resistances. 
(c) The potential difference across each resistance. 
 Ans. [(a) 10 kΩ (b) 1 mA (c) 2 V, 8 V]


14.6: Two resistances of 6 KΩ and 12 kΩ are connected in parallel. A 6V battery is connected across its ends, find the values of the following quantities:

(a) Equivalent resistance of the parallel combination. 
(b) Current passing through each of the resistances. 
(c) Potential difference across each of the resistance. 
 Ans. [(a) 4 kΩ, (b) 1 mA,0.5 mA (c) 6 V]


14.7: An electric bulb is marked with 220 V, 100 W. Find the resistance of the filament of the 14.8 bulb. If the bulb is used 5 hours daily, find the energy in kilowatt-hours consumed by the bulb in one month (30 days). Ans. (484 Ω, 15 kWh)


14.8: An incandescent light bulb with an operating resistance of 95 Ω is labelled "150 W". Is this bulb designed for use in a 120 V circuit or a 220 V circuit? Ans. (It has been designed for 120 V)

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14.9: A house is installed with 
(a) 10 bulbs of 60 W each of which are used 5 hours daily. 
(b) 4 fans of 75 W each of which run 10 hours daily. 
(c) One T.V. of 100 W which is used for 5 hours daily. 
(d) One electric iron of 1000 W which is used for 2 hours daily. If the cost of one unit of electricity is Rs.4. 

Find the monthly expenditure of electricity (one month=30 days). Ans. (Rs. 1020/-)


14.10: A 100W lamp bulb and a 4 kW water heater are connected to a 250V supply. Calculate 
(a) the current which flows in each appliance 
(b) the resistance of each appliance when in use. 
 Ans.[(a)0.4 A, 16 A, (b) 625 Ω, 15.26 Ω]


14.11: A resistor of resistance 5.6 Ω is connected across a battery of 3.0V by means of a wire of negligible resistance. A current of 0.5A passes through the resistor. Calculate 
(a) Power dissipated in the resistor. 
(b) Total power produced by the battery. 
(c) Give the reason of difference between these two quantities. 
 Ans. [(a) 1.4W (b) 1.5W (c) some power is lost by the internal resistance of the battery]