NAT MCQs

A molecular formula is a whole-number multiple of the empirical formula.
It applies to substances composed of discrete molecules.

Balancing follows conservation of atoms and mass.
Coefficients change amounts, not chemical formulas.

Equation coefficients give stoichiometric ratios.
They may be interpreted as molecule or mole ratios.

Once the limiting reactant is used up, no more product can form.
Other reactants may remain in excess.

A body in rotational equilibrium has no angular acceleration.
Clockwise and counterclockwise torques balance.

Work is W=Fd when force and displacement are parallel.
W=20×5 = 100 J.

Use W=Fd cosθ.
W=10×4×cos60° = 20 J.

Kinetic energy is ½mv².
K=½×4×9 = 18 J.

K=½mv².
K=½×2×100 = 100 J.

Potential energy change is mgh.
5×10×8 = 400 J.

Power is work divided by time.
P=600/3 = 200 W.

Energy transferred is Pt.
1000×20 = 20,000 J.