Q4 of 5 Page 127

A current of 1 ampere flows in series circuit contains an electric lamp and a conductor of 5 ohms when connected to a 10V battery. Calculate the resistance of the electric lamp. Now if a resistance of 10 ohms is connected in parallel with this series combination what change in current flowing through 5-ohm conductor and the potential difference across the lamp will take place? Give reason.

According to the question we make following circuit diagram.


Let be the resistance of bulb and both the resistances are in series.


So, Net Resistance = ( + 5) ohm


Also, V = 10 volts and I = 1 A


So, using Ohm’s Law:




Ohms


Now, a resistance of 10 ohms is connected in parallel.



Now, resultant resistance =


So,


Now, and


So, Voltage across 5 Ohm resistance =


= 5 V


And Voltage across bulb =


= 5 V


More from this chapter

All 5 →
1

A potentiometer wire of length 1m has a resistance of 10 ohms. It is connected to a 6V battery in series with a resistance of 5 ohms. Determine the EMF of a primary cell 'e' which gives a balance point of 40 cm.

 2

What is Kirchhoff’s second law?

 3

Two students X and Y experiment potentiometer separately using the circuit diagram here. Keeping other things unchanged (i) X increases the value of resistance R (ii) Y decreases the value of resistance S in the setup. How will these changes affect the position of the null point in each case and why?

 5

State Ohm's law and mention its limitations.