What amount of current would pass through a 10 Ω coil if it takes 21s for the coil to just melt a lump of ice of mass 10g at 0oC if there are no heat losses? (Latent heat of fusion of ice = 336 Jg\(^{-1}\)).

  • A 16.00A
  • B 4.00 A
  • C 0.50A
  • D 0.25A
  • E 0.06 A
waec 1993physics

The correct answer is B. 4.00 A

I\(^2\)Rt = mI;

I = \(\sqrt{\frac{mI}{Rt}}\)

= \(\sqrt{\frac{10 \times 336}{10 \times 21}}\)

= \(\sqrt{16}\)

= 4.0A

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