In sodium sulphate (Na₂SO₄), the mass percent of sodium, sulfur and oxygen is:

1. 32.4%, 45.05%, 22.6%

2. 22.6%, 45.05%, 32.4%

3. 32.4%, 22.6%, 45.05%

4. 45.05%, 32.4%, 22.6%

If the mass of air at sea level is 1034 g cm^–2, pressure in pascal will be:

1. 1.01332 x 10⁵ Pa

2. 1.01332 x 10⁶ Pa

3. 1.01332 x 10⁷ Pa

4. 1.01332 x 10⁸ Pa

The SI unit of mass is:

1. Kilogram (kg)

2. Gram (g)

3. Pascal (Pa)

4. Kilometres (km)

A significant figure is defined as :

If the speed of light is 3.0 × 10⁸ m s^–1, then the distance covered by light in 2.00 nanoseconds will be -

1. 0.500 m

2. 0.600 m

3. 0.700 m

4. 0.800 m

15.15 pm in the basic unit will be 

1. 1.515 x 10^-12 m

2. 2.57 x 10^-11 m

3. 2.87 x 10^-11 m

4. 1.515 x 10^-11 m

The number of significant figures present in the answer of the following calculations [(i), (ii), (iii)]  are respectively -

The numbers 234,000 and 6.0012 can be represented in scientific notation as -

1. $2.34\times {10}^{-9} \mathrm{and} 6\times {10}^3$

2. 0.234 $\times {10}^{-6}$ and $60012\times {10}^{-9}$

3. $2.34\times {10}^{-9} \mathrm{and}$ $6.0012\times {10}^{-9}$

4. 2.34$\times {10}^5$ and 6.0012$\times {10}^0$

The number of significant figures in the numbers 5005, 500.0, and 126,000 are, respectively: