# Archives

## A body weighs 49 N on a spring balance at the north pole. What will be its weight recorded on the same weighing machine, if it is shifted to the equator?

[Use g = GM/R2 = 9.8 ms-2 and radius of earth, R = 6400 km.] a. 49 N b. 49.83 N c. 49.17 Nd d. 48.83 N Answer: (d) At North Pole, weight... View Article

## If the source of light used in a Young’s double slit experiment is changed from red to violet:

a. the fringes will become brighter. b. consecutive fringe lines will come closer. c. the central bright fringe will become a dark fringe. d.... View Article

## The logic circuit shown below is equivalent to :

The logic circuit shown below is equivalent to : Answer: (2) The answer is option 2... View Article

## Match List – I with List-II.

Match List - I with List-II. List – I List - II (a) Source of microwave frequency ( i) Radioactive decay of nucleus (b)... View Article

## When a particle executes SHM, the nature of graphical representation of velocity as a function of displacement is:

a. elliptical b. parabolic c. straight line d. circular Answer: (a) We know that in SHM; V = ω√(A2 - x2) Elliptical Alternate: x = A... View Article

## Given below are two statements: Statement I: PN junction diodes can be used to function as transistor, simply by connecting two diodes, back to back, which acts as the base terminal. Statement II: In the study of transistor, the amplification factor β indicates ratio of the collector current to the base current.

In the light of the above statements, choose the correct answer from the options given below. a. Statement I is false but Statement II is true.... View Article

## A circular hole of radius (a/2) is cut out of a circular disc of radius ‘a’ shown in figure. The centroid of the remaining circular portion with respect to point ‘O’ will be:

A circular hole of radius (a/2) is cut out of a circular disc of radius ‘a’ shown in figure. The centroid of the remaining circular... View Article

## On the basis of kinetic theory of gases, the gas exerts pressure because its molecules:

a. suffer change in momentum when impinge on the walls of container. b. continuously stick to the walls of container. c. continuously lose... View Article

## An X-ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be:

a. 10-2 nm b. 10-3 nm c. 10-4 nm d. 10-1 nm Answer: (b) The minimum wavelength of photon will correspond to the maximum energy due to... View Article

## According to Bohr atom model, in which of the following transitions will the frequency be maximum?

a. n = 2 to n = 1 b. n = 4 to n = 3 c. n = 5 to n = 4 d. n = 3 to n = 2 Answer: (a) Since, ΔE is maximum for the transition from n = 2 to... View Article

## Zener breakdown occurs in a p-n junction having p and n both:

a. lightly doped and have wide depletion layer. b. heavily doped and have narrow depletion layer. c. heavily doped and have wide depletion layer.... View Article

## Dichromate ion is treated with base, the oxidation number of Cr in the product formed is:

Answer: 6 Cr2O72- + 2OH- ⇌ 2CrO42- + H2O For CrO42- x + (–2 × 4) = –2 x = 6... View Article

## A certain gas obeys P(Vm – b) = RT. The value of (∂Z/∂P)T is xb/RT. The value of x is ______.

Answer: 1 P(v – b) = RT PV – Pb = RT Z = 1 + PV/RT dZ/dP = 0 + b/RT b/RT = xb/RT x = 1... View Article

## For a chemical reaction A +B ⇌ C + D (ΔrHψ = 80 kJ mol–1) the entropy change ΔrSψ depends on the temperature T (in K) as ΔrSψ = 2T (J K–1 mol–1). Minimum temperature at which it will become spontaneous is ________K.

For a chemical reaction A +B ⇌ C + D (ΔrHψ = 80 kJ mol–1) the entropy change ΔrSψ depends on the temperature T (in... View Article

## Number of bridging CO ligands in [Mn2(CO)10] is _____.

Number of bridging CO ligands in [Mn2(CO)10] is _____. Answer: 0 Fact Hence the answer is 0... View Article

## The number of significant figures in 50000.020 × 10–3 is _______.

Answer: 7 50000.020 × 10–3 Number of significant figures = 7... View Article

## 3.12 g of oxygen is adsorbed on 1.2 g of platinum metal. The value of oxygen adsorbed per gram of the adsorbent at 1 atm and 300 K in L is _______.

[R = 0.0821 L atm K–1 mol–1] Answer: 2 Moles of O2 = 3.12/32 = 0.0975 volume of O2 = nRT/P = (0.0975 ×0.082×300)/1 volume... View Article

## Consider the following reaction

Consider the following reaction MnO4- + 8H+ + 5e– → Mn+2 + 4H2O, Eo = 1.51 V. The quantity of electricity required in Faraday to... View Article

## 224 mL of SO2(g) at 298 K and 1 atm is passed through 100 mL of 0.1 M NaOH solution. The non-volatile solute produced is dissolved in 36 g of water. The lowering of vapour pressure of solution (assuming the solution is dilute) (P(H2O)= 24 mm of Hg) is 10–2 x mm of Hg, the value of x is _____

Answer: 0.18 The balanced equation is SO2 + 2NaOH → Na2SO3 + H2O moles of NaOH = molarity × volume (in litre) = 0.1 × 0.1 = 0.01... View Article