# Archives

## The equiconvex lens has focal length f. If is cut perpendicular to the principal axis passin through optical centre, then focal length of each half is (1) f/2 (2) f (3) 3f/2 (4) 2f

Answer: (4) Len's Maker's formula is given by where f is the focal length (half the radius of curvature) n is the refractive index of the... View Article

## Seven digits from the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 are written down non-repeatedly in a random order to form a seven digit number. The probability that this seven digit number is divisible by 9 is (1) 2/9 (2) 7/36 (3) 1/9 (4) 7/12

Answer: (3) We know that the integer is divisible by 9 if the sum of its digits is divisible by 9. Sum of the first 9 natural numbers is n(S) =... View Article

## The A.M. of the first ten odd numbers is (1) 10 (2) 100 (3) 1000 (4) 1

Answer: (1) Arithmetic Mean (A.M) - Sum of all of the numbers of a group, when divided by the number of items in that list. The first ten odd... View Article

## Concentrated aqueous solution of sulphuric acid is 98% by mass and has density of 1.80g mL?1. What is the volume of acid required to make one liter 0.1M H2SO4 solution? (1) 16.65mL (2) 22.20mL (3 ) 5.55mL (4) 11.10mL

Answer: (3) Molarity of H2SO4 solution = number of moles of the solute/Volume of solution given in terms of litres Molarity of H2SO4 solution =... View Article

## The length breadth and height of a room are in the ratio 3 : 2 : 1. If the breadth and height are halved while the length is doubled, then total area of the four walls of the room will (1) Remain the same (2) Decrease by 30% (3) Decrease by 15% (4) Decrease by 18.75%

Answer: (2) Let us consider the room with Length (l) = 3x Breadth (b) = 2x Height = 1x Area of the walls (A) = 2(l + b) × h A = 2(3x + 2x)... View Article

## The refractive index of water is 4 / 3 and that of glass is 5/3. What will be the critical angle for the ray of light entering water from the glass (1) sin?1 (4/5) (2) sin?1 (5/4) (3) sin?1 (1/2) (4) sin?1 (2/1)

Answer: (1) At a critical angle, the ray of light entering the water from glass would be refracted at 90?. Snell’s law is defined as... View Article

## The bond order of CO molecule on the basis of molecular orbital theory is: (1) Zero (2) 2 (3) 3 (4) 1

Answer: (3) The bond order shows the number of chemical bonds present between a pair of atoms. The Bond Order Formula can be defined as half of... View Article

## What is meant by term bond order? Write bond orders for N2, O2?

Answer: The bond order shows the number of chemical bonds present between a pair of atoms. The Bond Order Formula can be defined as half of the... View Article

## The moment of inertia of a square lamina about the perpendicular axis through its centre of mass is 20 kg per metre square then its moment of inertia about an axis touching its side and in the plane of the lamina will be

Answer: Given parameters Moment of inertia of a square lamina about the perpendicular axis at the center of the square (I0) = 20 kgm-2 Let us... View Article

## Two numbers are in the ratio 5:6. If 8 is subtracted from each of the numbers , the ratio becomes 4:5 find the numbers.

Answer: Let us consider the two numbers are x and y Given: x/y = 5/6 x × 6 = y × 5 6x - 5y = 0....................(1) If 8 is subtracted... View Article

## Two water taps together can fill a tank in 9 (3/8) hours. The tap of larger diameter takes 10 hrs less than the smaller one to fill the tank separately. Find the time in which each tap can separately fill the tank.

Answer: Let the tap with smaller diameter fills the tank alone in x hours Let the tap with larger diameter fills the tank alone in (x - 10)... View Article

## A motorboat whose speed in still water is 18 km/h, takes 1 hour more to go 24 km upstream than to return downstream to the same spot. Find the speed of the stream.

Answer: Given parameters: The speed of the motorboat in still water =18 kmph Let us consider The speed of the stream = s Speed of boat... View Article

## The dimensional formula for permittivity of free space (?0) in the equation F = (1/4??0) (q1q2/r2) where, symbols have their usual meaning is (1)

Answer: The permittivity of free space Dimensions of F = [MLT-2] Dimensions of q = [AT] Dimensions of r = [L]... View Article

## The distance of closest approach of an alpha-particle fired towards a nucleus with momentum p is r. If the momentum of the alpha-particle is 2p, the corresponding distance of closest approach is (1) 4r (2) 2r (3) 2/r (4) r/4

Answer: (4) All of the kinetic energy of incident particles is converted to the potential energy of the system at the distance of closest... View Article

## Pneumatophores occur in (1) Carnivorous plants (2) Free-floating hydrophytes (3) Halophytes (4) Submerged hydrophytes

Answer: (3) Pneumatophores are respiratory roots which are found in halophytes such as mangroves. Halophytes grow in saline swamps, hence... View Article

## In albuminous seeds, food is stored in ……… and in exalbuminous seeds, food is stored in ………… (1) Endosperm, cotyledons (2) Cotyledons, cotyledons (3) Cotyledons, endosperm (4) Endosperm, endosperm

Answer: (1) The majority of the monocotyledonous seeds are albuminous seeds, i.e., they have thick, swollen endosperms for nourishment. The... View Article

## Polycot is a mixture of __________. (a) Cotton and nylon (b) Polyester and nylon (c) Polyester and cotton (d) Wool and polyester

Answer: (c) Polyester and cotton Polycot is obtained by mixing polyester and cotton. Polycot is popular polyester used in textile manufacturing... View Article

## What is meant by teminism??

Answer: Teminism is a theoretical concept. nIt is actually know as Reverse Transcription. This was first discovered in 1978 by Temin and... View Article

## Who is the father of genetic engineering? (1) Steward Linn (2) Stanley Cohen (3) Paul Berg (4) Kary Multis

Answer: (4) In 1972 Paul Berg began genetic engineering. With the assistance of the lambda phage, he was able to introduce an SV-40 virus gene... View Article

## Write any two solutions of the equation x+y=7

Answer: Given x + y = 7.................(1) Let us consider x = 1 Then equation (1) becomes 1 + y = 7 y = 6 Let us consider x = 2 Then... View Article