Environment-resistor temperature

[signo]

Hello to everybody, first of all sorry for my English (I'm Italian).

I have a circuit, enclosed in a plastic box, where there is power
resistor 1K, 50W and Tmax=200 degrees centigrade.
On the resistor is not present any heat sink.

After few hours that the circuit is working, the temperature measured
on the case of the resistor (Tr) reaches 110 degrees, in a
environmental temperature (Te) of 20 degrees.

My boss says that if Te increases50 degrees (Te = 20+50 =70 degrees),
Tr will increase the same value (Tr = 110+50 = 160 degrees).

I would say that Tr will increase, but not so much, just a little bit.
In my opinion it will be reduced the time for the resistor of reaching
the maximum value.

Is my boss right? Am I right? Are we both wrong?

Thank to everybody is going to help me about this matter.

Massimo

 

[signo]

well... to be honest he is not an engineer, I'm an engineer.. I am
deeply ashamed...

 

[signo]

Yesterday I've tried to test Tr with Te variable (from 20 degrees to 35
degrees).
I can say that, with a tollerance of one degree, approximately the
variation of Te is the same of the variation of Tr.

Thanks to everybody,
Massimo