Question

How much wil be the heat developed if 0.4 A current flows through a conductor of resistance 400 Ohm for 5 min

Answer 1

GIVEN :-

• Current ( I ) = 0.4 A

• Resistance ( R ) = 400 Ω

• Time ( t ) = 5 × 60 seconds

TO FIND :-

• Heat developed

SOLUTION :-

 We know that,

  V = IR

 $\longrightarrow \sf V = 0.4 \times 400 \\\\\longrightarrow \bf V= 160 \ V$

Formulas to find heat developed,

  $\bullet \sf \ \boxed{\bf H = I^2Rt} \\\\\bullet \sf \ \boxed{\bf H = VIt } \\\\\bullet \sf \ \boxed{\bf H=\dfrac{V^2 t}{R}}$

METHOD 1 :-

 $\longrightarrow \sf H = I^2Rt\\\\\longrightarrow H = 0.4\times 0.4 \times 400 \times 5\times 60 \\\\\longrightarrow\bf H=19200 \ J$

METHOD 2 :-

 $\longrightarrow \sf H= VIt \\\\\longrightarrow H = 160\times 0.4\times 5\times 60\\\\\longrightarrow \bf H = 19200 \ J$

METHOD 3 :-

 $\longrightarrow \sf H =\dfrac{V^2t}{R} \\\\\longrightarrow H = \dfrac{160\times 160\times 5\times 60}{400} \\\\\longrightarrow H = \dfrac{7680000}{400}\\\\\longrightarrow \bf H = 19200 \ J$