The significant figures in 1.0024, 1.240 and 0.0020 are respectively

• 5, 4, 2

• 3, 3, 1

• 5, 3, 4

• 5, 3, 2

A golf-ball weigh 40.0 gm. If it is moving with a velocity of 20.0 ms^-1, it's de-Broglie wavelength is

• 1.66 x 10^-34 nm

• 8.28 x 10^-32 nm

• 8.28 x 10^-25 nm

• 1.66 x 10^-24 nm

Which is the shortest wavelength line in the Lyman series of the hydrogen spectrum? (R= 1.097 x 10^-2 nm^-1)

• 94.21 nm

• 91.16 nm

• 911.6 nm

• 933.6 nm

4.

Which of the following order of ionisation energy is correct?

• B < Be < N < C

• Be > B > C > N

• B < Be < C < N

• Be < B < C < N

Volume of CO₂ obtained from complete decomposition of 20 g CaCO₃ at STP is

• 2.24 litre

• 4.48 litre

• 20 litre

• 22.4 litre

The shape of an orbital is determined by

• n

• l

• m

• s

The enthalpies of all elements in their standard states are

• zero

• >0

• <0

• unity

Which of the following, is not a unit of pressure?

• Atmosphere

• Torr

• Pascal

• Newton

Which of the following ions, has smallest size?

• Ca²⁺

• Cl^-

• S^2-

• K⁺

Which of the following acids is monobasic?

• H₃PO₃

• H₃PO₂

• H₂SO₃

• H₃PO₄