✓ Board-verified
Physics · 2025 · 2 marks
Moving Charges and MagnetismMagnetic Field due to a Current Element, Biot-Savart Law2 marksApplyvery short answer
CBSE 2025 · Region 5 · Set 3 · Q18
A current of 5 A is passing along +X direction through a wire lying along X -axis. Find the magnetic field B at a point r =(3 i +4 j ) m due to 1 cm…
A current of $\displaystyle 5$ A is passing along +X direction through a wire lying along X -axis. Find the magnetic field $\displaystyle \overrightarrow{\mathrm{B}}$ at a point $\displaystyle \overrightarrow{\mathrm{r}}=(3 \hat{\mathrm{i}}+4 \hat{\mathrm{j}}) \mathrm{m}$ due to $\displaystyle 1$ cm element of the wire, centered at origin.
Marking-scheme solution
Using Biot-Savart's law:
$\displaystyle \vec{B}=\frac{\mu_{0}}{4 \pi} \frac{I d \vec{l} \times \vec{r}}{r^{3}}$
$\displaystyle =\frac{\left(10^{-7}\right)\left[5\left(10^{-2}\right) \hat{i} \times(3 \hat{i}+4 \hat{j})\right]}{5^{3}}$
$\displaystyle =1.6 \times 10^{-10} \hat{k} \mathrm{~T}$
All Moving Charges and Magnetism questions2025 question paperNCERT solutions: Moving Charges and MagnetismPractice Moving Charges and Magnetism →
More from Moving Charges and Magnetism
- A 2.0 cm segment of wire, carrying 5.0 A current in positive y-direction lies along y -axis, as shown in the figure. The magnetic field at a point (3…2024
- Two thin long parallel wires A and B are separated by a distance r and carry current I each in the same direction. The force per unit length exerted…2023
- Derive an expression for the magnetic field B, due to a circular coil of N turns, each of radius r carrying current I, at a distance ' x ' from the…2026
- Assertion: A proton and an electron enter a uniform magnetic field B with the same momentum p such that p is perpendicular to B. They describe…2024
- Beams of electrons and protons move parallel to each other in the same direction. They2023
- (i) A particle of mass m and charge q is moving with a velocity v in a magnetic field B as shown in the figure. Show that it follows a helical path.…2024
- Figure shows a narrow beam of electrons entering with a velocity of 3 × 10^7 m / s, symmetrically through the space between two parallel horizontal…2026
- A particle of mass m and charge q moving with a uniform velocity v=v_0 x i+v_0 y j enters a region with a magnetic field B=B_0 j. After some time, an…2023
CBSE Class 12 Physics past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.