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Question
Choose the correct statements(s):
(a) All quantities may be represented dimensionally in terms of the base quantities.
(b) A base quantity cannot be represented dimensionally in terms of the rest of the base quantities.
(c) The dimensions of a base quantity in other base quantities is always zero.
(d) The dimension of a derived quantity is never zero in any base quantity.
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Solution
The statements which are correct are:
(a) All quantities may be represented dimensionally in terms of the base quantities.
(b) A base quantity cannot be represented dimensionally in terms of the rest of the base quantities.
(c) The dimensions of a base quantity in other base quantities is always zero.
Statement (d) is not correct because A derived quantity can exist which is dimensionless for example fine structure constant which is given by
\[\alpha = \frac{2\pi e^2}{hc} = \frac{1}{137}\]
\[\text{ where e is the electric charge and c is the speed of light and h is Planks constant . }\]
\[\alpha \text{ is a derived quantity and is dimensionless .}\]
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