Current Electricity
 

Section A: Objective Type Questions

  1. Electric current is the flow of _________. a. Protons b. Electrons c. Neutrons d. Positrons

  2. The resistance of a conductor depends on its ____________. a. Length and temperature b. Cross-sectional area and resistivity c. Voltage and current d. Charge and potential difference

  3. The unit of resistivity is _________. a. Ohm-meter b. Coulomb c. Ampere d. Joule

  4. Kirchhoff's first law is based on the principle of ___________. a. Conservation of charge b. Conservation of energy c. Conservation of momentum d. Conservation of mass

  5. The time constant of an RC circuit depends on the ___________. a. Resistance and capacitance of the circuit b. Voltage and current of the circuit c. Temperature of the circuit d. Length of the circuit

  6. The potential difference across a resistor is directly proportional to the ____________. a. Resistance of the resistor b. Current flowing through the resistor c. Voltage applied across the resistor d. Length of the resistor

  7. A potentiometer is a device used to measure ____________. a. Resistance of a conductor b. Current flowing through a conductor c. Voltage of a cell d. All of the above

  8. Joule's law of heating states that the heat generated in a conductor is proportional to ___________. a. Voltage applied across the conductor b. Current flowing through the conductor c. Resistance of the conductor d. All of the above

  9. The magnetic field around a current-carrying wire is ___________. a. Circular b. Spherical c. Cylindrical d. Rectangular

  10. A cyclotron is a device used to ____________. a. Measure the magnetic field b. Generate an electric field c. Accelerate charged particles d. Create a vacuum

Section B: Short Answer Type Questions

  1. State Ohm's law and derive its mathematical expression.
  2. Define resistivity and state its SI unit. Explain how it is related to the conductivity of a material.
  3. Explain the concept of internal resistance of a cell and how it affects the output voltage of the cell.
  4. State Kirchhoff's laws and explain their significance in current electricity.
  5. Derive the expression for the capacitance of a parallel-plate capacitor in terms of its area, separation, and dielectric constant.

Section C: Long Answer Type Questions

  1. Derive the expression for the resistance of a conductor in terms of its length, cross-sectional area, and resistivity. How does the resistance of a wire change with temperature?
  2. Explain the phenomenon of drift velocity and derive its expression in terms of electric field, relaxation time, and mobility of charge carriers.
  3. Describe the construction and working of a meter bridge. How is it used to measure the resistance of a conductor?
  4. Explain the principle of a potentiometer and how it can be used to measure the emf of a cell.
  5. Define the term 'magnetic field' and explain how it is related to the current flowing through a conductor. Explain the working principle of a cyclotron and how it is used to accelerate charged particles.