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Few statements regarding the distribution of electrons in the energy shells are given. Which of the following statements is not correct?

A For fourth energy shell (N), the maximum number of electrons is 32 according to 2n² rule.
B When N is the outermost shell of an atom, it can accommodate a maximum of 8 electrons only.
C The filling of the fourth shell begins even before the third shell is completely filled.
D Fifth shell can accommodate 50 electrons according to 2n² rule.

A solid sphere of radius 5 cm floats in water. If a maximum load of 0.1 kg can be put on it without wetting the load, then the density of the material of the sphere is (Density of water = 1000 kg m^-3)

A 960 kg m^-3
B 900 kg m^-3
C 850 kg m^-3
D 800 kg m^-3

If 3.01 × 10²⁰ molecules are removed from 98 mg of
H₂SO₄, then number of moles of H₂SO₄ left are
(Given : Atomic mass of H = 1 u, O = 16 u, S = 32 u)

A 0.5 × 10^-3 mol
B 0.1 × 10^-3 mol
C 9.95 × 10^-2 mol
D 1.66 × 10^-3 mol.

Study the given figure carefully and select the incorrect statement(s).

I. A white ring is formed which is closer to the hydrochloric acid end of the tube because hydrogen chloride fumes diffuse faster than ammonia.
II. Ratio of number of atoms of ammonia to that of hydrogen chloride which combine to form 3.6138 × 10²⁴ atoms of ammonium chloride is 1 : 3.
III. 3.4 g of ammonia combines with 7.3 g of hydrogen chloride to form 10.7 g of ammonium chloride.
IV. If temperature is increased, white ring will be formed exactly in the middle of the tube.
(Given : Atomic mass of H = 1 u, N = 14 u, Cl = 35.5 u)

A II and IV only
B II and III only
C I, II and IV only
D I only

The outer shell electrons in compound PQ₃ are shown in the given figure.

Which of the following could be the correct representation of elements P and Q?

Which part of the Earth is the coolest?

A Core
B Crust
C Mantle
D All of these

Three blocks A, B and C, of masses 4 kg, 2 kg and 1 kg respectively, are in contact on a frictionless surface, as shown in the figure. If a force of 14 N is applied on the 4 kg block, then the contact force between A and B is


A 8 N
B 4 N
C 2 N
D 6 N

Mass spectrum of an element Q having two isotopes Q₁ and Q₂ is shown in the given graph.

If Q₂ is 8.082 times heavier than ¹²C and Q₁ is 7.833 times heavier than ¹²C then, the molecular mass of compound, QO₁ will be approximately
(Given : Atomic mass of O = 16 u)

A 94 u
B 128 u
C 96 u
D 125 u.

Two point objects A and B having masses in the ratio 4 : 3 are separated by a distance of 1 m. When another point object C of mass M is placed in between A and B, the force between A and C is (1/3)^rd of the force between B and C. Then, the distance of C from A is

A
B
C
D

Gloria is holding her hand quite close to the side of a candle flame without feeling hot. This is because

AAir is a gas and is a poor conductor of heat.
BAir is highly inflammable
CCandle flame does not produce heat.
DNone of these