An incandescent bulb has a thin filament of t | vedclass

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(C) $1$. As the tungsten filament evaporates non-uniformly, its cross-sectional area decreases at various points, leading to an increase in resistance

Vedclass · Accepted Answer

$C, D$

Vedclass · Answer

(C) $1$. As the tungsten filament evaporates non-uniformly, its cross-sectional area decreases at various points, leading to an increase in resistance $(R = ho L / A)$.$2$. Since the bulb is powered at a constant voltage $(V)$, the power consumed is given by $P = V^2 / R$. As $R$ increases, the power consumed $P$ decreases. Thus, statement $(D)$ is true.$3$. Due to non-uniform evaporation, the filament becomes thinner at certain points, causing non-uniform temperature distribution. Thus, statement $(A)$ is false.$4$. As the filament thins, its resistance increases, not decreases. Thus, statement $(B)$ is false.$5$. As the filament thins, the temperature at the thinnest points increases, shifting the peak of the black-body radiation spectrum towards higher frequencies (Wien's displacement law, $\lambda_{max} T = 	ext{constant}$). Therefore, it emits more light in the higher frequency band before breaking. Thus, statement $(C)$ is true.$6$. Therefore, statements $(C)$ and $(D)$ are correct.

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