The answer is
A) 1.3 x 10-7
The electromotive force (∈) = 2 V
<h3>Further explanation</h3>
Given
I=2 A
t = 30 s
E = 120 J
Required
The electromotive force (∈)
Solution
The electromotive force : the potential difference between two electrodes in galvanic cell
Can be formulated :

E = energy, J
Q = charge , Coulomb = i.t

Control rods<span> are </span>rods<span>, plates, or tubes containing a neutron absorbing material (material with high absorbtion cross-section for thermal neutron) such as boron, hafnium, cadmium, etc., used to </span>control<span> the power of a nuclear reactor.
so the statement that describe a control rod is:
</span><span>Control rods are lowered into the reactor to slow down the reaction by absorbing neutrons.</span>
Hi There,
This is False.
Hope this helped!