I can confirm, your answer is 800J (Or 800 Joules)!
I just took the test and this was the correct answer :)
Answer:
The answer is (d) is totally reflected
Explanation:
Using the total internal reflection concept.
This concept state that:
"If the angle of incidence is greater than the critical angle then the light will not refract but it will reflect back totally"
Using the above statement, as incident angle is 42 degree and critical angle is 41 degree it means incident angle is greater than the critical angle. Therefore, light will not refract but it will totally reflected.
According to Ohm's Law:

Where: V = Voltage
I = Current
R = Resistance
As you can see here, you can say that Current is directly proportional to Voltage and indirectly proportional to Resistance. This means that as the voltage increases, current increases and as the resistance increases, current decreases.
So in your scenario, if the voltage remains the same, but the resistance is doubled, that means that the current will be halved.
So the answer to your question is 2. the current will drop to half of its original value.