I think it’s d because it talks about a spring with is common like the spring in a pen
Answer:

Explanation:
The capacitance of a parallel plate capacitor is given by:
(1)
where
is the vacuum permittivity
A is the area of the plates
d is the separation between the plates
The charge stored on the capacitor is given by
(2)
where C is the capacitance and V is the voltage across the capacitor.
The displacement current in the capacitor is given by
(3)
where t is the time elapsed
Substituting (1) and (2) into (3), we find an expression for the displacement current:

where we have



Substituting into the equation, we find

Answer: option d: The nucleus of Atom Q is more stable than the nucleus of Atom P.
Explanation:
Atom P is radioactive and disintegrates, it emits beta particles (high speed electrons or positrons) because it is not stable. On disintegration, it forms a stable Atom Q which is non-radioactive and thus it does not disintegrates further.
Thus, the correct option is only d. The nucleus of Atom Q is more stable than the nucleus of Atom P.
Answer:
thermal decomposition reaction
Explanation:
Answer:
Magnification m is 2.5cm
Explanation:
This problem bothers on lenses
Given data
Object distance u= 4cm
Height of object v= 10 cm
The problem is quite straightforward seeing that object and image distances are given
We know that the magnification
m= size of image/size of object
m= v/u= 10/4 = 2. 5cm
What is a convex lens
A convex lens is a type of lens that has the centre thicker than the ends, the thickness at the centre makes the lens surface to curve outward. Convex lens causes close light rays of light to converge at a point after refraction.