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
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
Which of the following ions, has smallest size?
Ca2+
Cl-
S2-
K+
A.
Ca2+
Ca2+, Cl-, S2- and K+ are isoelctronic species. In isoelectronic ions, size decrease with increasing nuclear charge. Hence, Ca2+ ion is the smallest among these.