Numerical Examples | Chapter 11 | Electricity | Physics 11 | National Book Foundation | FBISE 2025

For latest videos, click on the following link: https://whatsapp.com/channel/0029VaGr... What is meant by drift velocity? Why we use Kirchhoff’s law for circuit problems solution. Define Kirchhoff’s current rule and Kirchhoff’s voltage rule. What is the working principle of Galvanometer? What is LDR? Explain. Explain the electronic current in a metallic wire as due to the drift of free electrons in the wire. Explain the term the following terms. A) Drift velocity B) emf C) internal resistance What is potential divider? Explain. What is Wheatstone bridge? Explain in detail. What is a potentiometer? Explain. Discuss Kirchhoff’s laws in detail. If 1A current flows through a copper wire having 1〖cm〗^2 area of cross-section and 10km length; also calculate the time required by charge carrier to travel from one to other end of the conductor (Free electron density of copper is 8.5×〖10〗^28 per m^3). Calculate the flow of charges per unit time inside the emf source having potential 2V and terminals are connected with each other having internal resistance 0.02Ω Calculate the terminal potential of the emf source if internal resistance of the battery is 10Ω and current and internal potential are 1A and 10V respectively? There is a copper coil having 2000 number of turns with 0.8mm^2 cross-section are, the length per turn is 80cm. Calculate the resistance of the coil? (Resistivity of copper is 0.02μΩm? A piece of silver wire has a resistance of 1Ω. What will be the resistance of magnum wire of one third of the length and one third of diameter, if the specific resistance of wire is 30 times that of silver? Calculate the current that flows in the 1Ω resistor in the following circuit. 11.1 A current of 3A is flowing in a copper conductor with a cross-section of 𝟏〖𝒎𝒎〗^𝟐. Find the drift velocity of the electrons. (For copper, 𝒏=𝟖.𝟓×〖𝟏𝟎〗^𝟐𝟖 𝒎^(−𝟑)). 11.2 What is the potential difference between two points in an electric field if it takes 600J of energy to move a charge of 2C between these two points? 11.3 Calculate the resistance of wire 10m long that has a diameter of 2mm and resistivity of 𝟐.𝟔𝟑×〖𝟏𝟎〗^(−𝟐) 𝛀𝒎. 11.4 Calculate 1 month cost of using 50W energy saver for 8 hours daily in your study room. Assume that the price of a unit is Rs 20. 11.5 Find current flowing through each resistor, using Kirchhoff’s law, in the given circuit 11.1 A wire of diameter 𝟎.𝟎𝟐𝒎 contains 〖𝟏𝟎〗^𝟐𝟖 free electrons per 𝒎^𝟑. For an electric current of 𝟏𝟎𝟎𝑨. Find the drift velocity for free electrons in the wire. 11.2 Calculate the current passing through a conducting material having cross-section area 𝟏〖𝒄𝒎〗^𝟐 and after applying constant potential across conductor electrons acquire 𝟏.𝟓×〖𝟏𝟎〗^(−𝟐) 𝒎/𝒔 and free electron density is 〖𝟏𝟎〗^𝟐𝟒 𝒆𝒍𝒆𝒄𝒕𝒓𝒐𝒏𝒔/〖𝒎𝒆𝒕𝒆𝒓〗^𝟑. 11.3 A wire has length 10m with its resistance 100ohm, if wire is stretched as its length is increased 3 times, how much the resistance of the wire will be increased? 11.4 Estimate the cost of electricity consumed for a month of one year (365 years), if the following devices are used as specified: (i) 10 bulbs of 40 watts for 10 hours. (ii) 10 fridges of 250 watts for 24 hours. (iii) 40 tube lights of 25 watts for 10 hours. (Given the rate of electricity is Rs 50/unit) 11.5 Find the current flowing through each resistors in the circuit having two loop, as shown in the figure.