Assertion: Units of Rydberg constant R are m^-1

Reason: It follows from Bohr’s formula $\overline{v}=R\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$, where the symbols have their usual meaning.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion : Parallex method cannot be used for measuring distances of stars more than 100 light years away.

Reason : Because parallex angle reduces so much that it cannot be measured accurately.

Assertion : Number of significant figures in 0.005 is one and that in 0.500 is three.

Reason : This is because zeros are not significant.

Assertion: Mass, length and time are fundamental physical quantities.

Reason: They are independent of each other.

Assertion : Density is a derived physical quantity.

Reason : Density cannot be derived from the fundamental physical quantities.

Assertion: Nowadays a standard metre is defined in terms of the wavelength of light.

Reason: Light has no relation with length.

Assertion: Surface tension and surface energy have the same dimensions.

Reason: Because both have the same S.I. unit

Assertion : In $y=A\sin (\omega t-kx),$ $(\omega t-kx)$ is dimensionless.

Reason : Because dimension of $\omega =\left[M^0{L}^{0}T\right].$

Assertion : Radian is the unit of plane angle.

Reason : One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius of the circle.