Table of Contents
Electricity and magnetism are two fascinating aspects of physics that are deeply interconnected. The chapter “Magnetic Effects of Current” introduces students to this relationship, helping them understand how electric currents produce magnetic fields and how these fields influence their surroundings. This concept is fundamental to understanding various technologies we use in our daily lives, such as electric motors, generators, transformers, and electromagnets.
In this worksheet, we will explore the key concepts and principles related to the magnetic effects of current, including magnetic fields, field lines, and rules to determine their direction. You’ll learn about important phenomena like electromagnetic induction, which explains how changing magnetic fields generate electric currents. Rules such as the Right-Hand Thumb Rule and Fleming’s Left-Hand Rule will help you visualize and predict the behavior of magnetic fields and forces in different situations.
The worksheet also dives into practical applications, from solenoids and electromagnets to large-scale uses in industries like transportation and medicine. These concepts not only provide a foundation for advanced physics topics but also help you relate theoretical knowledge to real-world applications.
Do Check: NCERT Solutions for Class 10 Science Chapter 13 Magnetic effects of electric current
Key Concepts of Magnetic Effects of Current
1. Magnetic Field
- A magnetic field is the region around a magnet where the force of magnetism can be felt.
- It is represented by magnetic field lines, which show the direction and strength of the field.
- Properties of Magnetic Field Lines:
- Magnetic field lines never intersect.
- They are closed loops, starting from the North Pole and ending at the South Pole outside the magnet.
- The closer the field lines, the stronger the magnetic field.
2. Magnetic Field Due to a Current-Carrying Conductor
- When an electric current flows through a conductor, it produces a magnetic field around it.
- Right-Hand Thumb Rule is used to determine the direction of the magnetic field:
- If you hold a current-carrying conductor in your right hand such that the thumb points in the direction of current, the curled fingers show the direction of the magnetic field.
3. Magnetic Field Due to a Straight Conductor
- The magnetic field around a straight current-carrying conductor forms concentric circles.
- The strength of the magnetic field decreases as the distance from the conductor increases.
4. Magnetic Field Due to a Circular Loop
- When current flows through a circular loop, the magnetic field is stronger at the center of the loop.
- Increasing the number of turns in the loop increases the strength of the magnetic field.
5. Magnetic Field Due to a Solenoid
- A solenoid is a long coil of wire with many turns, through which current flows.
- The magnetic field inside a solenoid is strong, uniform, and similar to the field of a bar magnet.
- The solenoid can act as an electromagnet when a soft iron core is placed inside it.
6. Electromagnetic Induction
- When a conductor moves in a magnetic field, an electric current is induced in the conductor. This phenomenon is called electromagnetic induction.
- Faraday’s Laws of Electromagnetic Induction:
- An induced current is produced when there is a change in the magnetic field.
- The magnitude of the induced current depends on the rate of change of the magnetic field.
7. Fleming’s Left-Hand Rule
- This rule is used to find the direction of force experienced by a current-carrying conductor in a magnetic field.
- Stretch your left hand such that the thumb, forefinger, and middle finger are mutually perpendicular:
- Thumb: Direction of force (motion)
- Forefinger: Direction of magnetic field
- Middle finger: Direction of current
8. Fleming’s Right-Hand Rule
- This rule is used to determine the direction of induced current when a conductor moves in a magnetic field.
- Stretch your right hand such that the thumb, forefinger, and middle finger are mutually perpendicular:
- Thumb: Direction of motion of conductor
- Forefinger: Direction of magnetic field
- Middle finger: Direction of induced current
Do Check: Extra Questions – Magnetic Effects of Electric Current – CBSE Class 10 Science
Applications of Magnetic Effects of Current
- Electric Motor
- Converts electrical energy into mechanical energy.
- Uses the force experienced by a current-carrying conductor in a magnetic field to rotate the coil.
- Electric Generator
- Converts mechanical energy into electrical energy.
- Works on the principle of electromagnetic induction.
- Transformer
- Transfers electrical energy between two circuits.
- Steps up or steps down voltage levels.
- Electromagnets
- Temporary magnets created by passing current through a coil.
- Used in cranes, electric bells, and MRI machines.
- Domestic Appliances
- Devices like fans, mixers, and washing machines use the principle of the magnetic effects of current.
Class 10 Physics Magnetic Effects of Current Worksheet 1
Objective Questions
- What is the direction of the magnetic field inside a solenoid? a) Parallel to the axis of the solenoid
b) Perpendicular to the axis of the solenoid
c) Circular around the solenoid
d) Random
(Answer: a) - Which rule is used to determine the direction of the magnetic field around a current-carrying conductor?
(Answer: Right-Hand Thumb Rule) - Name the device that converts electrical energy into mechanical energy.
(Answer: Electric Motor)
Fill in the Blanks
- The magnetic field produced by a current-carrying solenoid is similar to that of a _________.
(Answer: Bar Magnet) - An induced current is produced when there is a _________ in the magnetic field around a conductor.
(Answer: Change) - Electromagnets are widely used in _________ and _________ industries.
(Answer: Cranes, MRI)
Short Answer Questions
- State the Right-Hand Thumb Rule.
(Answer: If you hold a current-carrying conductor in your right hand with the thumb pointing in the direction of the current, the curled fingers show the direction of the magnetic field.) - What happens when a current flows through a solenoid?
(Answer: A strong and uniform magnetic field is created inside the solenoid, and the solenoid acts as an electromagnet.) - How does an electric generator work?
(Answer: An electric generator works on the principle of electromagnetic induction. When a coil is rotated in a magnetic field, a current is induced in the coil.)
Numerical Problems
- A solenoid has 500 turns and a current of 2 A flows through it. If the length of the solenoid is 0.5 m, calculate the magnetic field inside the solenoid.
(Formula: B = μ₀ × (n × I), where n = Number of turns/Length) - A wire carries a current of 5 A. Calculate the magnetic field at a distance of 2 cm from the wire.
(Formula: B = μ₀ × I / (2πr))
Class 10 Physics Magnetic Effects of Current Worksheet 2: Conceptual Questions
Multiple-Choice Questions (MCQs)
- What does the closeness of magnetic field lines indicate?
a) Strength of magnetic field
b) Direction of electric current
c) Polarity of a magnet
d) Type of material
(Answer: a) - The strength of the magnetic field inside a solenoid increases with:
a) Increase in the number of turns
b) Decrease in current
c) Increase in distance from the solenoid
d) Use of an aluminum core
(Answer: a) - Which device works on the principle of electromagnetic induction?
a) Transformer
b) Electric motor
c) Electromagnet
d) Electric generator
(Answer: d)
Fill in the Blanks
- The direction of induced current is given by _________ rule.
(Answer: Fleming’s Right-Hand Rule) - The magnetic field lines around a straight current-carrying conductor are in the shape of _________.
(Answer: Concentric Circles) - A _________ core is used to increase the strength of a solenoid.
(Answer: Soft Iron)
True or False
- The magnetic field produced by a current-carrying conductor depends on the direction of current.
(Answer: True) - The magnetic field inside a solenoid is weaker than outside it.
(Answer: False) - Electromagnets are permanent magnets.
(Answer: False)
Short Answer Questions
- What is the role of a soft iron core in a solenoid?
(Answer: A soft iron core increases the strength of the magnetic field by concentrating the field lines.) - Why do magnetic field lines never intersect?
(Answer: If they intersect, it would mean two directions of the magnetic field at the same point, which is not possible.) - Define electromagnetic induction.
(Answer: Electromagnetic induction is the process by which a changing magnetic field induces an electric current in a conductor.)
Class 10 Physics Magnetic Effects of Current Worksheet 3: Numerical Problems
Problem Set
- A current of 3 A flows through a straight conductor. Calculate the magnetic field at a distance of 4 cm from the wire.
(Use: B = μ₀ × I / 2πr; μ₀ = 4π × 10⁻⁷ T·m/A) - The number of turns in a solenoid is 400, and its length is 0.8 m. If the current through the solenoid is 2.5 A, calculate the magnetic field inside the solenoid.
(Use: B = μ₀ × (n × I); n = Number of turns/Length) - A loop of wire has a radius of 10 cm and carries a current of 5 A. Calculate the magnetic field at the center of the loop.
(Use: B = μ₀ × I / (2R))
(Hint: Convert radius to meters.)
Class 10 Physics Magnetic Effects of Current Worksheet 4: Diagram-Based Questions
Draw and Label
- Draw a neat and labeled diagram of:
- Magnetic field lines around a bar magnet.
- Magnetic field lines due to a current-carrying straight conductor.
- A solenoid with its magnetic field.
- Identify and label the poles of the solenoid shown in the diagram below (provide a sample image or ask students to visualize one).
- Use Fleming’s Left-Hand Rule to determine the direction of motion of a conductor in the provided diagram (include a question diagram with a labeled magnetic field and current).
Class 10 Physics Magnetic Effects of Current Worksheet 5: Application-Based Questions
Short Answer Questions
- How can you convert a solenoid into a temporary magnet?
(Answer: By passing an electric current through the solenoid and inserting a soft iron core inside it.) - Write two differences between an electromagnet and a permanent magnet.
(Answer: An electromagnet is temporary and works only when current flows through it, while a permanent magnet retains its magnetism.) - Explain the working principle of an electric motor.
(Answer: An electric motor works on the principle that a current-carrying conductor placed in a magnetic field experiences a force.)
Case Study
A school science project involves building an electromagnet to lift small objects. The students use a solenoid with 500 turns, and a current of 3 A flows through it.
- What factors can increase the strength of the electromagnet?
- Suggest any two real-life applications of electromagnets.
(Answers: Increase the number of turns, use a stronger current, and insert a soft iron core; Applications: Cranes to lift scrap metal, electric bells.)
Class 10 Physics Magnetic Effects of Current Worksheet 6: Higher-Order Thinking Skills (HOTS)
Problem-Solving Questions
- A student notices that the needle of a magnetic compass deflects when placed near a current-carrying wire. Explain why this happens and what the direction of deflection indicates.
- Design an experiment to show that the direction of the magnetic field changes when the direction of current is reversed in a conductor.
Critical Thinking
- Why are electromagnets preferred over permanent magnets in certain devices like cranes?
(Answer: Electromagnets can be turned on or off, and their strength can be controlled, making them more versatile.) - If the Earth’s magnetic field disappeared suddenly, how would it affect the functioning of a compass?
(Answer: A compass would stop working because it relies on Earth’s magnetic field for navigation.)
