Question

A long solenoid is formed by winding 20 turns/cm. The current necessary to produce a magnetic field of 20 millitesla inside the solenoid will be approximately

$\left( \frac { \mu _ { 0 } } { 4 \pi } = 10 ^ { - 7 } \right.$ Tesla - metre / ampere $)$

• A. 8.0 A
• B. 4.0 A
• C. 2.0 AC
• D. 1.0 A

Answer 1

Answer: (A)

8.0 A

Answer 2

$B = \mu _ { 0 } n i$; where $n = \frac { 20 } { 10 } \frac { \mathrm { turn } } { \mathrm { cm } }$ =$20 \times 10 ^ { - 5 }$

$= 4 \pi \times 2000 \times i$ $\Rightarrow$