Practice questions Class 10

 CLASS 10 SCIENCE – HOTS QUESTIONS

Magnetic Effects of Electric Current

Based on the given NCERT concept: Direction of magnetic field and Fleming’s Left-Hand Rule

Instructions: Answer all questions with proper reasoning. Use Fleming’s Left-Hand Rule wherever applicable.

1. A positively charged particle is moving towards the west and is deflected towards the north by a magnetic field. In which direction is the magnetic field acting? Explain your reasoning.

HOTS type: Conceptual reasoning

2. A student says, “If a positively charged particle is deflected towards the north, the magnetic field must also be towards the north.” Identify the error in the statement and explain the correct relationship.

HOTS type: Error analysis

3. A positively charged particle moving towards the west is deflected towards the north. If the direction of its motion is reversed while the magnetic field remains unchanged, what will be the new direction of force? Give a reason.

HOTS type: Reversal of direction

4. An electron and an alpha particle enter the same magnetic field with the same velocity direction. If both experience magnetic force, will their force directions be the same or opposite? Explain using the sign of charge.

HOTS type: Charge comparison

5. A current-carrying conductor experiences a force towards the north while the current flows towards the west. Determine the direction of the magnetic field using Fleming’s Left-Hand Rule.

HOTS type: Fleming’s Left-Hand Rule

6. In a metallic conductor, electrons move opposite to the direction of conventional current. If a student applies Fleming’s Left-Hand Rule using the electron-flow direction as the current direction, will the predicted force be correct? Explain.

HOTS type: Conventional current vs electron flow

7. The current in a conductor is reversed and, at the same time, the magnetic field is also reversed. Predict whether the direction of force on the conductor changes or remains the same. Justify your answer.

HOTS type: Two changes together

8. A conductor carrying current is placed in a magnetic field, but no force is observed on it. A student concludes that there is no magnetic field. Is this conclusion necessarily correct? Give a possible reason.

HOTS type: Critical thinking

9. A positively charged particle moving towards the west experiences a force vertically upward. A student gives four possible directions for the magnetic field: north, south, vertically upward and vertically downward. Which one is correct? Explain.

HOTS type: Direction from observation

10. Why is it necessary to know the direction of conventional current, rather than simply the direction of electron motion, when applying Fleming’s Left-Hand Rule? Explain in the context of a metallic conductor.

HOTS type: Application and explanation

S Answers

1. Vertically upward. Using \(F=q(v\times B)\), westward motion and northward force require an upward magnetic field.

2. Incorrect. Magnetic force is perpendicular to both the particle's motion and the magnetic field.

3. South. Reversing the velocity reverses the direction of magnetic force.

4. Opposite directions. The electron is negatively charged, while the alpha particle is positively charged.

5. Vertically upward. This follows from Fleming’s Left-Hand Rule.

6. No. Fleming’s Left-Hand Rule uses conventional current, not electron flow.

7. Remains the same. Reversing both current and magnetic field leaves the force direction unchanged.

8. No. The conductor may be parallel to the magnetic field, so the force is zero.

9. South. For a positive charge moving west with force upward, the magnetic field is southward.

10. Because Fleming’s Left-Hand Rule uses conventional current. In a metal, conventional current is opposite to electron flow.