Answer:

Explanation:
When an electromagnetic wave passes through the interface between two mediums, it undergoes refraction, which means that it bents and its speed and its wavelength change.
In particular, the wavelength of an electromagnetic wave in a certain medium is related to the index of refraction of the medium by:

where
is the wavelength in a vacuum (air is a good approximation of vacuum)
n is the refractive index of the medium
In this problem:
is the original wavelength of the wave
n = 1.47 is the index of refraction of corn oil
Therefore, the wavelength of the electromagnetic wave in corn oil is:

Considering the unknown resistence as R and using the Ohm's First Law, we have:
The equivalent resistence is given by the resistor series with the lamp resistence.

If you notice any mistake in my english, please let me know, because i am not native.
Answer:
B. An Iron Bar place in a room becomes cooler than its surroundings.
Answer:
Total work done in expansion will be 
Explanation:
We have given pressure P = 2.10 atm
We know that 1 atm 
So 2.10 atm 
Volume is increases from 3370 liter to 5.40 liter
So initial volume 
And final volume 
So change in volume 
For isobaric process work done is equal to 
So total work done in expansion will be 
The energy goes from electric energy and gets converted into thermal energy.