Magnetic Effect of Current Physics - Magnetic Effect of Current

A uniform conducting wire $\text{ABC}$ has a mass of $10g.$ A current of $2A$ flows through it. The wire is kept in a uniform magnetic field $B = 2T. $The acceleration of the wire will be

• A
  Zero
• ✓
  $12\ ms^{-2}$ along $y-$axis
• C
  $1.2 \times 10^{-3} ms^{-2}$ along $y-$axis
• D
  $0.6 \times 10^{-3} ms^{-2}$ along $y - $axis

Answer: B.

In the given figure net magnetic field at $O$ will be

• A
  $\frac{2 \mu_0 \mathrm{i}}{3 \pi \mathrm{a}} \sqrt{4-\pi^2}$
• ✓
  $\frac{\mu_0 \mathrm{i}}{3 \pi \mathrm{a}} \sqrt{4+\pi^2}$
• C
  $\frac{2 \mu_0 \mathrm{i}}{3 \pi \mathrm{a}^2} \sqrt{4+\pi^2}$
• D
  $\frac{2 \mu_0 \mathrm{i}}{3 \pi \mathrm{a}} \sqrt{4-\pi^2}$

Answer: B.

An infinitely long straight conductor is bent into the shape as shown in the figure. It carries a current of $i$ ampere and the radius of the circular loop is $r$ metre. Then the magnetic induction at its centre will be

• A
  $\frac{2 \mathrm{i}}{\mathrm{r}}(\pi+1) \frac{\mu_0}{4 \pi}$
• ✓
  $\frac{2 i}{r}(\pi-1) \frac{\mu_0}{4 \pi}$
• C
  Zero
• D
  Infinite

Answer: B.

• A
  $1.25 \ cm$
• B
  $ 2.5 \ cm$
• C
  $ 12.5 \ cm$
• ✓
  $ 25.0 \ cm$

Answer: D.

Two thick wires and two thin wires, all of the same materials and same length form a square in the three different ways $P, Q$ and $R$ as shown in fig with current connection shown, the magnetic field at the centre of the square is zero in cases

• A
  In $P$ only
• B
  In $P$ and $Q$ only
• C
  In $Q$ and $R$ only
• ✓
  $P$ and $R$ only

Answer: D.