Pakistan MCQs

Atomic number identifies the element.
In a neutral atom it also equals the number of electrons.

Opposite collinear vectors subtract in magnitude.
The resultant magnitude is |12-7| = 5 N.

Mass number applies to a specific isotope.
It is always a whole number.

Displacement is a vector from initial to final position.
It can be zero even when distance traveled is not zero.

Isotopes have the same atomic number but different mass numbers.
Their chemical behavior is usually similar.

Distance is a scalar and depends on the actual path.
It is always nonnegative.

Ions form by gaining or losing electrons.
Cations are positive and anions are negative.

Average speed uses total path length.
It does not depend on direction.

A cation forms when electrons are lost.
It has more protons than electrons.

Average velocity is a vector based on net displacement.
A round trip can have zero average velocity.

Vector addition replaces multiple vectors with an equivalent single vector.
Its direction and magnitude depend on the original vectors.

Slope gives change in displacement per unit time.
That is the definition of velocity.