1. Given situation

An incandescent bulb has a tungsten filament. Due to long use, tungsten evaporates non-uniformly, so some parts become thinner than others.

The bulb is operated at constant voltage.

We must judge each statement.

2. Physical effect of non-uniform thinning

For a small section of filament, $R = \rho \frac{\ell}{A}$ where $A$ is cross-sectional area.

As tungsten evaporates, $A$ decreases in some regions. Hence for those regions, $R \uparrow$ So the resistance of small thinned sections increases with time.

Therefore, statement B is false.

3. Will temperature remain uniform?

The power dissipated per small section is $P_i = I^2 R_i$ Since thinner portions have larger $R_i$, they generate more heat locally.

So the filament develops hot spots; temperature is not uniform.

Therefore, statement A is false.

4. Effect on emitted radiation

A hotter region emits black-body radiation with peak shifting to higher frequency according to Wien’s law: $\lambda_{\max} T = \text{constant}$ So if temperature increases locally, the emitted spectrum shifts toward smaller wavelength / higher frequency.

As the filament becomes non-uniform and some regions get hotter before breaking, it emits relatively more light in the higher frequency band.

Therefore, statement C is true.

5. Effect on total electrical power at constant voltage

The bulb is connected to constant voltage $V$, so total power is $P = \frac{V^2}{R_{\text{total}}}$

As parts of the filament become thinner, their resistance increases, so overall filament resistance tends to increase. Thus, $R_{\text{total}} \uparrow \implies P \downarrow$

Hence towards the end of life, the bulb consumes less electrical power.

Therefore, statement D is true.

6. Option-wise conclusion

• A: False
• B: False
• C: True
• D: True

So the correct options are $\boxed{C, D}$

7. Comparison with stored answer

Stored correct answer: C, D

My derived answer matches the stored answer.