We have that the work function of the metal

From the Question we are told that
UV radiation (λ = 162 nm)
Kinetic energy 
Generally the equation for Kinetic energy is mathematically given as


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Answer:
Option (A) the solid X is ground to a fine powder.
Explanation:
X(s) + 2B(aq) → X+(aq) + B2(g)
In the reaction above, the rate of the reaction will be highest, when X being a solid is ground to fine powder.
Grounding X to fine powder simply means increasing the surface area of X.
An increase in surface area of reactants will definitely increase the rate of reaction because the particles of the solid will collide with the right orientation and hence speed up the reaction rate.
High temperature and pressure produce the highest rate of reaction. However, this must be balanced with the high cost of the energy needed to maintain these conditions. Catalysts increase the rate of reaction without affecting the yield. This can help create processes which work well even at lower temperatures.
I hope this helps you.
Answer:
500
Explanation:
from the average and if yoy multiple and then add your % and x you would get 500 to 600