Science Experiments

Question: My Physics Lab?

Sorry to bother you all…
I need help figuring out how to go about producing an experiment that answers this question.

“How much heat/watt does an incandescent bulb produced? How does the heat /watt vary with the wattage of the bulb?”

Does anyone have any ideas? I’m confused on what this stuff means because we never covered this during the school year. This serves as a substitute for a final exam and every kid gets a different question so all of the questions are kind of outside the curriculum…

Answer: Well the problem is the experimental setup!

Here it goes……
You’ll will need a box/container wuth ahole at the bottom big enough to accomodate the wires, to keep the incandescent bulb.

Keep the bulb in the lower portion. Divide the box into 2 compartment by a metal plate (it would be excellent if its copper)

Fix the plate touching the bulb from above and seal it so that water poured from above wont leak.

Also seal the bottomside of the box by cotton, felt etc.

The box acts as an insulated chamber.
Take a measured quantity of water at room temperature and pour it in the top chamber.

Put the bulb on. Wait for some time to let the system reach a steady state, keeping the voltage constant.

Since you know the initial temperature, quantity of water , you’ll find the temperature of the water now and calculate the heat gaind by water (Q) as:
Q = m*s*dT
m=mass
s = specific heat capacity of water
dT = temperature change.

Keep on varying voltage, and calculate Q every time.

You will get the answers required!

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