Question

Please answer the questions below

Answer 1

1ohm and 6 ohm are parallel and series with 3 ohm.
so effective resistance across terminal is...
$3 + \frac{1}{ \frac{1}{6} + \frac{1}{1} } = 3 + \frac{6}{7} = \frac{27}{7}$
so, current= 8/(27/7)=56/27= approx 2

Answer 2

If you rearrange the circuit, you will get the three resistors in parallel ( potential difference is same across all the resistors and they are connected to same terminal points in circuit).

Equivalent R = (3 × 6 × 1)/(3×6 + 6×1 + 1×3)

= 18 / 27 = 2/3 ohm

given, Potential difference = E = 8 V

so,

current = I = E/R = 8/(2/3) = 8×3/2 = 12 A.....

so, answer : (C) 12 A

**********************************

que. 72.


Magnetic Field due current carrying loop at the centre of the loop =
B = ui / 2R...........(1)

where, i - current through the loop
R - Radius of the loop

the loop/ circumference of the loop makes angle 360° at the centre.
..

so, arc that subtend angle "theta" at the centre produces the field = (theta / 360°) (ui/2R)

so,

field strength = (60°/360°)(ui/2R)
= ui / 12R...


so,
answer: (D) ui/12R.....

hope, it helped you.