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Physics · 2025 · 2 marks
CBSE 2025 · Region 1 · Set 2 · Q17
Show that E =ρ j leads to Ohm's law. Write a condition in which the Ohm's law is not valid for a material.
Show that $\displaystyle \overrightarrow{\mathrm{E}}=\rho \overrightarrow{\mathrm{j}}$ leads to Ohm's law. Write a condition in which the Ohm's law is not valid for a material.
Marking-scheme solution
$\displaystyle \vec{E}=\rho \vec{j}$
$\displaystyle \frac{V}{l}=\rho \frac{I}{A}$
$\displaystyle \frac{V}{I}=\rho \frac{l}{A}=$ constant (Ohm's Law)
Condition for non-validity of Ohm's Law:
High temperature / in semiconductor
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