What is the formula to find out the mechanical advantage in a lever?

1. $\dfrac {\text {Effort}}{\text {Load}}\\[1em]$
2. $\dfrac {\text {Load arm}}{\text {Effort arm}}\\[1em]$
3. $\dfrac {\text {Effort arm}}{\text {Load arm}}\\[1em]$
4. $\dfrac{\text {Length}}{\text {Height}}$

$\dfrac {\text {Effort arm}}{\text {Load arm}}\\[1em]$

Reason — The ratio of the load lifted by a machine to the effort applied on it is defined as mechanical advantage and is given by

$\text {Mechanical Advantage (M.A.)} = \dfrac{\text {Load}}{\text {Effort}}$ …………… (i)

And,

Mechanical advantage of a lever is given by the ratio of the effort arm to the load arm i.e.,

$\text {Mechanical Advantage (M.A.)} = \dfrac{\text {Effort arm}}{\text {Load arm}}$ …………… (ii)

From (i) and (ii)

$\Rightarrow \text {Mechanical Advantage (M.A.)} = \dfrac{\text {Load}}{\text {Effort}} = \dfrac{\text {Effort arm}}{\text {Load arm}}$