JEE Mains · Physics · STD 12 -Electromagnetic induction
- JEE Mains 2024
- Medium
- MCQ
A coil is placed perpendicular to a magnetic field of 5000 T . When the field is changed to 3000 T in 2 s , an induced emf of 22 V is produced in the coil. If the diameter of the coil is 0.02 m , then the number of turns in the coil is _______.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) 70
Step-by-step Solution
Detailed explanation
\(\varepsilon=N\left(\frac{\Delta \phi}{t}\right)\)
\(\triangle \phi=(\triangle B) A\)
\(B_i=5000 T\)
\(B_f=3000 T\)
\(d =0.02 m\)
r = 0.01 m
\(\triangle \phi=(\triangle B) A\)
\(=(2000) \pi(0.01)^2=0.2 \pi\)
\(\varepsilon=N\left(\frac{\Delta \phi}{t}\right) \Rightarrow 22=N\left(\frac{0.2 \pi}{2}\right)\)
\(N=70\)
\(\triangle \phi=(\triangle B) A\)
\(B_i=5000 T\)
\(B_f=3000 T\)
\(d =0.02 m\)
r = 0.01 m
\(\triangle \phi=(\triangle B) A\)
\(=(2000) \pi(0.01)^2=0.2 \pi\)
\(\varepsilon=N\left(\frac{\Delta \phi}{t}\right) \Rightarrow 22=N\left(\frac{0.2 \pi}{2}\right)\)
\(N=70\)
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