The correct option is D.
A step up voltage transformer is a type of transformer which increases voltage from primary to secondary turns. The transformer has more secondary winding turns than primary winding turns. A step up transformer is designed to increase voltage because high voltage increases efficiency.<span />
Answer:

Explanation:
<u>Variable Isolation</u>
It's a common practice when dealing with equations that we have to isolate one variable in terms of other variables and/or constants. The isolation of the variable usually implies adding, subtracting, multiplying or dividing by constants. The following example shows how to isolate the A:

We are required to find the equation where the variable has a coefficient of 1 and isolate it. The following equation fits into the description:

Isolating B:

The process is denitrification
The formula for the time period oscillation of a spring is:
T = 2π√(m/k) where m is the mass of the object attached to the spring and k is the spring constant of the spring.
Multiplying m by 4 we have:
2π√(4m/k)
= 2π x 2√(m/k)
or 2 x (2π√(m/k)) or 2T.
Therefore, when object is four times as massive, then period will double.