Archives

When a metallic surface is illuminate with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is 4V. The threshold wavelength for the metallic surface is (1) 4λ (2) 5λ (3) 5/2λ (4) 3λ

Answer: (4) 3λ The Threshold frequency is known as the minimum wavelength for the photoelectric effect that the light should have. If the... View Article

If the change in the value of g at a height h above the surface of the earth is the same as at a depth d below it. When both d and h are much smaller than the radius of earth, then (1) d = h (2) d = h² (3) d = h/2 (4) d = 2h

Answer: (4) d = 2h Acceleration due to gravity is the acceleration gained by an object due to gravitational force. Its SI unit is m/s2. It has... View Article

The ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series in the spectrum of hydrogen is_______

Answer: 5/27 Transition to n=1 and n=2 are refered to as Lyman and Balmer series. For Lyman Series wavelength will be longest when energy the... View Article

How do you simplify i^(-999)?

Answer: The value of i is √-1. The imaginary unit number is used to express the complex numbers, where i is defined as imaginary or unit... View Article

Which of the following chemicals dubstance has the strongest hydrogen bond? (1) HCl (2) H₂O (3) HI (4) H₂S

Answer: (2) H2O The strongest hydrogen bond is formed by an atom with a small size and a larger electronegative charge. Oxygen (O) is smaller in... View Article

The sum of the measures of interior angles of a polygon of n sides is equal to (1) 2n right angles (2) (2n – 2) right angles (3) 2(n – 2) right angles (4) 2(n – 4) right angles

The sum of the measures of interior angles of a polygon of n sides is equal to (1) 2n right angles (2) (2n - 2) right angles (3) 2(n - 2) right... View Article

Which of the following sets of quantum numbers is correct for an electron in 3d-orbital? (1) n = 3, l = 2, m = -3 , s = +1/2 (2) n = 3, l = 3, m = +3, s = -1/2 (3) n = 3, l = 2, m = -2, s = +1/2 (4) n = 3, l = 2, m =-3, s = -1/2

Answer: The set of numbers used to describe the position and energy of the electron in an atom are called quantum numbers. There are four... View Article

How to find resultant of two vectors?

Answer: In Maths, the resultant vector is defined as the combination of two or more single vectors. We know that a vector is a quantity that has... View Article

The distance of the point (α, β) from origin is (1) α.β (2) α².β² (3) √α² – β² (4) √α² + β²

Answer: (4) √α2 + β2 The distance between two points is the length of the line segment, joining the given two points.... View Article

The solid ball density to be determined in an experiment. The diameter of the ball is measured with a screw gauge, whose pitch is 0.5mm and there are 50 divisions on the circular scale. The reading on the main scale is 2.5mm and that on the circular scale is 20 divisions. If the measured mass of the ball has a relative error of 2%, then the relative percentage error in the density is (1) 0.9% (2) 2.4% (3) 3.1% (4) 4.2%

Answer: (3) 3.1% The least count of the screw guage is defined as the distance moved by the tip of the screw when turned through one division of... View Article

Which of the following sets of concurrent forces may be in equilibrium? (1) F₁= 3N, F₂ = 5N, F₃ = 1N (2) F₁ = 3N, F₂ = 5N, F3 = 9N (3) F₁ = 3N, F₂ = 5N, F₃ = 6N (4) F₁ = 3N, F₂ = 5N, F₃ = 15N

Answer: (3) F1 = 3N, F2 = 5N, F3 = 6N According to the triangle law of forces If three concurrent forces are to be in equilibrium, the sum of... View Article

A particle P is moving in a circle of radius r with uniform speed v. C is the centre of the circle and AB in diameter. The angular velocity of P about A and C is in the ratio (1) 4 : 1 (2) 1 : 1 (3) 2 : 1 (4) 1 : 2

Answer: (4) 1: 2 Angular velocity is a vector quantity and is described as the rate of change of angular displacement which specifies the... View Article

A car of mass m is driven with acceleration a along a straight level road against a constant external resistive force R. When the velocity of the car is V, the rate at which the engine of the car is doing work will be________

Answer: The capacity to do work is termed Energy. The Energy expended to do work in unit time is termed as Power. It is represented as P. Power... View Article

Earth’s magnetic field always has a horizontal component except at (1) Magnetic poles (2) Magnetic equator (3) Geographical north pole (4) At an altitude of 45^o

Answer: (1) Magnetic poles Except at the magnetic pole, the Earth's magnetic field is always horizontal. At the magnetic pole, the earth's... View Article

The energy required to break one mole of Cl−Cl bonds in Cl2 is 242 kJ mol⁻¹. The longest wavelength of light capable of breaking single Cl−Cl bond is__________ (c = 3 × 10⁸ msec⁻¹, N_A = 6.023 × 10²³mol⁻¹) (1) 700nm (2) 640nm (3) 594nm (4) 492 nm

Answer: (4) 492 nm Bond energy is required to break the bond. Since breaking a bond requires energy, bond-energies are usually positive numbers.... View Article

If the p^th term of an AP is q and the q^th term is p, prove that its n^th term is (p + q – n).

Answer: A sequence of numbers that has a common difference between any two consecutive numbers is called an arithmetic progression (A.P.). The... View Article

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the % increase in the apparent frequency? (1) Zero (2) 0.5% (3) 5% (4) 20%

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the % increase in the... View Article

The correct statement for the molecule CsI₃ is that (1) it contains Cs⁺,I⁻ and lattice I₂ molecule (2) it contains Cs³⁺ and I⁻ ions (3) it is a covalent molecule (4) it contains Cs⁺ and I³⁻ ions

Answer: (4) it contains Cs+ and I-3 ions CsI3 → Cs+ + I3– CsI3 contains Cs+ and I3–. It is an ionic compound. Cs cannot... View Article

State the law of conservation of angular momentum and explain with a suitable example.

Answer: . The law of conservation of angular momentum states that when no external torque acts on an object, no change of angular momentum will... View Article

Which condition is not satisfied by an ideal solution? (1) Δ_mixH = 0 (2) Δ_mixV = 0 (3) Δ_mixS = 0 (4) Obeyance of Raoult’s law

Answer: (3) ΔmixS = 0 An ideal solution is a mixture in which the molecules of different species are distinguishable, however, unlike the... View Article

M	T	W	T	F	S	S
					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30
31