The unit of "impulse per unit area" is the same as that of

State,for each of the following physical quantities,if it is a scalar or a vector: volume,mass,speed,acceleration,density,number of moles,velocity,angular frequency,displacement,angular velocity.

Fill in the blanks:
$(a)$ To measure the direct distance of a mountain,....... is used.
$(b)$ For the measurement of time,the ........... clock is the most accurate.
$(c)$ Rounding off $15.753$ to three significant figures gives ....... .

Fill in the blanks:
$(a)$ $\frac{1\,\mu m}{1\,fm} = \,....$
$(b)$ The number of significant figures in $0.0060$ is $....$
$(c)$ To study nanotechnology,the $....$ microscope has been developed.

State whether the following statements are true or false:
$(a)$ Weight is a fundamental physical quantity.
$(b)$ $A$ micrometer is used to measure the size of an oleic acid molecule at the molecular level.
$(c)$ The dimensions of a derived quantity obtained from any fundamental quantity can never be zero.

Give an example of:
$(a)$ a physical quantity which has a unit but no dimensions
$(b)$ a physical quantity which has neither unit nor dimensions
$(c)$ a constant which has a unit
$(d)$ a constant which has no unit