A circular coil of radius $R$ having $N$ number of turns carries a steady current $I$. The magnetic induction at the centre of the coil is 0.1 tesla. If the number of turns is doubled and the radius is halved, which one of the following will be the correct value for the magnetic induction at the centre of the coil?

• A

  0.05 tesla
• B

  0.2 tesla
• Correct answer
  C

  0.4 tesla
• D

  0.8 tesla

Hence, the correct answer is option: 'C'.