A straight wire of length 50 cm carrying a current of 2.5 A is suspended in mid-air by a uniform magnetic field of 0.5 T (as shown in figure). The massof the wire is (`g = 10 ms^(-2)`)

Options

A. 62.5 gm
B. 250 gm
C. 125 gm
D. 100 gm

Answer

A

Explanation

Given,
Length of wire (1) `= 50 cm = 50xx10^(-2)m`
Current (I) = 2.5 A
Magnetic field (B) = 0.5 T
`g=10 ms^(-2)`
For the balance condition,
`F_(B)=mg`
BI1 = mg
`m=(BI1)/(g)=(0.5xx2.5xx50xx10^(-2))/(10)=62.5g`