1
AP EAPCET 2025 - 22nd May Evening Shift
MCQ (Single Correct Answer)
+1
-0

The length and area of cross-section of a copper wire are respectively 30 m and $6 \times 10^{-7} \mathrm{~m}^2$. If the resistivity of copper is $1.7 \times 10^{-8} \Omega \mathrm{~m}$, then the resistance of the wire is

A

$0.51 \Omega$

B

$0.68 \Omega$

C

$0.85 \Omega$

D

$0.75 \Omega$

2
AP EAPCET 2025 - 22nd May Evening Shift
MCQ (Single Correct Answer)
+1
-0

If current of 80 A is passing through a straight conductor of length 10 m , then the total momentum of electrons in the conductor is

(mass of electron $=9.1 \times 10^{-31} \mathrm{~kg}$ and charge of electron $=1.6 \times 10^{-19} \mathrm{C}$ )

A

$910 \times 10^{-9} \mathrm{Ns}$

B

$910 \times 10^{-11} \mathrm{Ns}$

C

$455 \times 10^{-9} \mathrm{Ns}$

D

$455 \times 10^{-11} \mathrm{Ns}$

3
AP EAPCET 2025 - 22nd May Evening Shift
MCQ (Single Correct Answer)
+1
-0

In a wire of radius 1 mm a steady current of 2 A uniformly distributed across the cross-section of the wire is flowing. Then the magnetic field at a point 0.25 mm from the centre of the wire is

A

$100 \mu \mathrm{~T}$

B

$200 \mu \mathrm{~T}$

C

$300 \mu \mathrm{~T}$

D

$400 \mu \mathrm{~T}$

4
AP EAPCET 2025 - 22nd May Evening Shift
MCQ (Single Correct Answer)
+1
-0

The magnetic field at the centre of a current carrying circular coil of radius $R$ is $B_c$ and the magnetic field at a point on its axis at a distance $R$ from its centre is $B_a$. The value of $\frac{B_c}{B_a}$ is

A

$\sqrt{2}$

B

$\frac{1}{2 \sqrt{2}}$

C

$2 \sqrt{2}$

D

$\frac{1}{\sqrt{2}}$