Potential energy because of the positions on gravatational field
Answer is Option C Lumen.It is also known as luminous energy.
Answer:
Torque,
Explanation:
Given that,
The loop is positioned at an angle of 30 degrees.
Current in the loop, I = 0.5 A
The magnitude of the magnetic field is 0.300 T, B = 0.3 T
We need to find the net torque about the vertical axis of the current loop due to the interaction of the current with the magnetic field. We know that the torque is given by :

Let us assume that, 
is the angle between normal and the magnetic field, 
Torque is given by :

So, the net torque about the vertical axis is
. Hence, this is the required solution.
<h2>Answer: Ion
</h2>
An ion is an atom that is electrically charged by <u>gaining or losing one or more electrons.
</u>
To understand it better:
An atom has a nucleus with electrons around it and has a neutral charge. When an electron is added or detached, this atom is electrically charged, that is, it ceases to have a neutral charge and becomes an <u>ion</u>.
In this sense, there are two types of ions:
-Anions: ions negatively charged, by the gain of electrons in the atom.
-Cations: ions positively charged, by the loss of electrons in the atom.