Question

Solve and answer both the question neglecting 'OR' in brief.​

Answer 1

We have,

$\longrightarrow\sf{H=\dfrac {V^2t}{R}}$

For constant $\sf{V}$ and $\sf{t},$

$\longrightarrow\sf{H\propto\dfrac {1}{R}\quad\quad\dots(1)}$

Here,

$\longrightarrow\sf{R_A=2\ \Omega}$

$\longrightarrow\sf{R_B=2\ \Omega+2\ \Omega=4\ \Omega}$

$\longrightarrow\sf{R_C=\dfrac {2\ \Omega\cdot2\ \Omega}{2\ \Omega+2\ \Omega}=1\ Omega}$

Hence,

$\longrightarrow\sf{R_C\ \textless\ R_A\ \textless\ R_B}$

Therefore, by (1),

$\longrightarrow\sf{H_C\ \textgreater\ H_A\ \textgreater\ H_B}$

Thus, heat produced is (c) maximum in C.

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We have,

$\longrightarrow\sf{R=\dfrac {V^2}{P}}$

Then,

$\longrightarrow\sf{\dfrac {R_1}{R_2}=\dfrac {P_2(V_1)^2}{P_1(V_2)^2}}$

$\longrightarrow\sf{\dfrac {R_1}{R_2}=\dfrac {20\times220^2}{40\times 100^2}}$

$\longrightarrow\sf{\bf{R_1:R_2=2.42:1}}$

Or,

$\longrightarrow\sf{\bf{R_1:R_2=2:1}}$