# Completely lost and need help

A 100-W lightbulb generates 95 W of heat, which is dissipated through a glass bulb that has a radius of 3.2cm and is 0.60mm thick.

What is the difference in temperature between the inner and outer surfaces of the glass?

i am completely lost and need help

## Answers and Replies

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haruspex
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Homework Helper
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A 100-W lightbulb generates 95 W of heat, which is dissipated through a glass bulb that has a radius of 3.2cm and is 0.60mm thick.

What is the difference in temperature between the inner and outer surfaces of the glass?

i am completely lost and need help
You need to know the thermal conductivity of the glass.

the thermal conductivity of glass is 0.84 J/(s*m*C)

what do i do with this

haruspex
Science Advisor
Homework Helper
Gold Member
the thermal conductivity of glass is 0.84 J/(s*m*C)

what do i do with this
Suppose you knew the temperature difference, the dimensions of the glass bulb and the glass thickness. How would you use that to find the rate of heat flow through the glass?