The magnetic force between wires as shown in figure is :- - Vidyadip

MCQ

The magnetic force between wires as shown in figure is :-

A
$\frac{{{\mu _0}i{I^2}}}{{2\pi }}\ln \left( {\frac{{x + l}}{{2x}}} \right)$
B
$\frac{{{\mu _0}i{I^2}}}{{2\pi }}\ln \left( {\frac{{2x + l}}{{2x}}} \right)$
✓
$\frac{{{\mu _0}i{I}}}{{2\pi }}\ln \left( {\frac{{x + l}}{x}} \right)$
D
None of these

✓

Answer

Correct option: C.

$\frac{{{\mu _0}i{I}}}{{2\pi }}\ln \left( {\frac{{x + l}}{x}} \right)$

c
Magnetic field at $\mathrm{dr}, \mathrm{B}=\frac{\mu_{0} \mathrm{I}}{2 \pi \mathrm{r}}$

Force on small element at a distance $r$ of wire of length $L$ is $d F=i(d r)\left(\frac{\mu_{0} I}{2 \pi r}\right)$

$\mathrm{F}=\frac{\mu_{0} \mathrm{i} \mathrm{I}}{2 \pi} \int_{\mathrm{x}}^{\mathrm{x}+\mathrm{L}} \frac{\mathrm{dr}}{\mathrm{r}}=\frac{\mu_{0} \mathrm{i} \mathrm{I}}{2 \pi} \ln \left(\frac{\mathrm{x}+\mathrm{L}}{\mathrm{x}}\right)$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 4. Moving charges and magnetism→4. Moving charges and magnetism — all question types→Physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

Vapour is injected at a uniform rate in a closed veseel which was initially evacuated. The pressure in the vessel:

$ABC$ is an equilateral triangle. Charges $ + \,q$ are placed at each corner. The electric intensity at $O$ will be

Two different metals are joined end to end. One end is kept at constant temperature and the other end is heated to a very high temperature. The graph depicting the thermo e.m.f. is

Penetrating power of $X$-rays increases with increase in

Following figure shows an ac generator connected to a "block box" through a pair of terminals. The box contains possible $R, L, C$ or their combination, whose elements and arrangements are not known to us. Measurements outside the box reveals that $e = 75\, sin\, (sin\, \omega\, t)\, volt,\, i = 1.5\, sin\, (\omega\, t + 45^o)\, amp$ then, the wrong statement is

If light travels a distance $x$ in $t_1 sec$ in air and $10 x$ distance in $t_2 sec$ in a medium, the critical angle of the medium will be

The light of two different frequencies whose photons have energies $3.8 \,eV$ and $1.4 \,eV$ respectively, illuminate a metallic surface whose work function is $0.6 \,eV$ successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectivly will be

Below figures $(1)$ and $(2)$ represent lines of force. Which is correct statement

The radius of inner most orbit of hydrogen atom is $5.3 \times 10^{-11}\,m$.$........\mathring A$ is the radius of third allowed orbit of hydrogen atom.

When is the angle of dip at a place equal to $45^{\circ}$ ?