Magnetic Effects Of Current And Magnetism Important Questions for NEET Physics - 2026

1. Multiple choice questions.

Q1. According to Biot-Savart law, the magnetic field at the center of a circular loop of radius $r$ carrying current $I$ is:

• (a) $\dfrac{\mu_0 I}{2r}$
• (b) $\dfrac{\mu_0 I}{4\pi r}$
• (c) $\dfrac{\mu_0 I}{r^2}$
• (d) $\dfrac{\mu_0 I r}{2}$

Answer: (a) $\dfrac{\mu_0 I}{2r}$

Q2. The force per unit length between two parallel, long straight conductors separated by distance $d$, each carrying current $I_1$ and $I_2$ in the same direction, is:

• (a) Attractive and equals $\dfrac{\mu_0 I_1 I_2}{2\pi d}$
• (b) Repulsive and equals $\dfrac{\mu_0 I_1 I_2}{2\pi d}$
• (c) Attractive and equals $\dfrac{\mu_0 I_1 I_2}{4\pi d}$
• (d) Repulsive and equals $\dfrac{\mu_0 I_1 I_2}{4\pi d}$

Answer: (a) Attractive and equals $\dfrac{\mu_0 I_1 I_2}{2\pi d}$

Q3. A moving coil galvanometer can be converted into an ammeter by connecting:

• (a) A high resistance in series
• (b) A low resistance in series
• (c) A high resistance in parallel
• (d) A low resistance in parallel

Answer: (d) A low resistance in parallel

Q4. The magnetic dipole moment of a current $I$ loop of area $A$ is:

• (a) $IA^2$
• (b) $2\pi I A$
• (c) $IA$
• (d) $I/A$

Answer: (c) $IA$

2. Very Short Answer (VSA).

Q1. State Ampere’s law in words.

Answer: Ampere’s law states that the line integral of the magnetic field around a closed loop is equal to $\mu_0$ times the net current enclosed by the loop.

Q2. Name a material that is strongly attracted by a magnet. Is it paramagnetic, diamagnetic, or ferromagnetic?

Answer: Iron is strongly attracted by a magnet. It is a ferromagnetic material.

Q3. What is the SI unit of magnetic dipole moment?

Answer: The SI unit of magnetic dipole moment is ampere meter squared ($A\,m^2$).

3. Short Answer Questions.

Q1. Explain the effect of temperature on ferromagnetic substances.

Answer: As temperature increases, the ferromagnetic property of the material decreases. Beyond a certain temperature called the Curie temperature, the substance becomes paramagnetic, losing its strong magnetism due to thermal agitation of the domains.

Q2. Describe the working principle of a moving coil galvanometer.

Answer: A moving coil galvanometer works on the principle that a current-carrying coil placed in a uniform magnetic field experiences a torque. This torque is proportional to the current and causes angular deflection, measured on the scale as electric current.

Q3. Derive the expression for the force acting on a charge $q$ moving with velocity $\vec{v}$ in a uniform magnetic field $\vec{B}$.

Answer:

1. A charge $q$ moving in a magnetic field $\vec{B}$ with velocity $\vec{v}$ experiences Lorentz force.
2. The force is given by $\vec{F} = q(\vec{v} \times \vec{B})$.
3. Its magnitude is $F = q v B \sin\theta$, where $\theta$ is the angle between $\vec{v}$ and $\vec{B}$.

4. True or False Questions.

Q1. The direction of force on a current-carrying conductor in a magnetic field is given by Fleming's right-hand rule.

Answer: False.

Q2. Bar magnet and solenoid have similar magnetic field lines.

Answer: True.

3. Fill in the Blanks Questions.

Q1. The conversion of a galvanometer to a voltmeter requires connecting a ________ resistance in series with it.

Answer: high

Q2. In the SI system, one ampere is defined using the force between ________ conductors carrying current.

Answer: two parallel

Scoring in NEET Physics: Magnetic Effects of Current and Magnetism

Learning the Magnetic Effects of Current and Magnetism helps you tackle both theory and numericals in the NEET Physics exam. Understanding key formulas and experiments boosts confidence and makes revision smoother.

Questions from topics like Biot-Savart law, Ampere's law, and magnetic force appear regularly in NEET. Practice of these topics helps in building speed and accuracy for competitive scoring in Physics.

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