An immersion heater with electrical resistance $7\,\,{\rm{\Omega }}$ is immersed in ${\rm{0}}{\rm{.1}}\,\,{\rm{kg}}$ of water at $20\,{\,^0}{\rm{C}}$ for ${\rm{3}}\,\,{\rm{min}}$. If the flow of current is ${\rm{4}}\,\,{\rm{A}}$, what is the final temperature of the water in ideal conditions? ${\left( {{\rm{Specific heat }}\,{\rm{capacity}}\,{\rm{ of }}\,{\rm{water}} = 4.2\,\, \times \,{{10}^3}\,\,{\rm{Jkg}}} \right)^{ - 1}}{{\rm{K}}^{ - 1}}$

JEE PHYSICS MCQ: CURRENT ELECTRICITY

1 Medium

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Application +4 | -1

An immersion heater with electrical resistance

7\,\,\mathrm{\Omega }

is immersed in

\mathrm{0}\mathrm{.1}\,\,\mathrm{kg}

of water at

20\,{\,^0}\mathrm{C}

for

\mathrm{3}\,\,\mathrm{min}

. If the flow of current is

\mathrm{4}\,\,\mathrm{A}

, what is the final temperature of the water in ideal conditions?

{\left( {\mathrm{Specific heat }\,\mathrm{capacity}\,\mathrm{ of }\,\mathrm{water} = 4.2\,\, \times \,{{10}^3}\,\,\mathrm{Jkg}} \right)^{ - 1}}{\mathrm{K}^{ - 1}}

View answer and explanation

Correct option: D

68\,{\,^0}\mathrm{C}

Option D (

68\,^0\mathrm{C}

) is correct because it is calculated by equating the heat generated by the immersion heater to the heat gained by the water.