JEE 2020: Weekly Quiz 22 (25.08.2019) for JEE & BITSAT Exams

Question 1

When an engine passes near to a stationary observer then its apparent frequencies occurs in the ratio 5/3. If the velocity of engine is-

Question 2

A whistle sends out 256 waves in a second. If the whistle approaches the observer with velocity 1/3 of the velocity of sound in air, the number of waves per second the observer will receive-

Question 3

A source of frequency n and an observer are moving on a straight line with velocities a and b respectively if the source is ahead of the observer and if the medium is also moving in the direction of their motion with velocity c (the velocity of sound being v) then the apparent frequency of sound heard by the observer would be

Question 4

A pipe open at both ends has a fundamental frequency f in air. The pipe is dipped vertically in water so that half of it is in water. The fundamental frequency of the air column is now:

Question 5

A uniform string of length 20 m is suspended from a rigid support. A short wave pulse is introduced at its lowest end. It starts moving up the string. The time taken to reach the support is:
(take

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Question 6

A particle of mass m is located in a one dimensional potential field where potential energy is given by V (x) = A (1 – cospx) , where A and p are constants .The period of small oscillations of the particle is

Question 7

Two indentical springs are connected to mass m as shown (K = spring constant). If the period of the configuration in (i) is 2 s, the period of the configuration (ii) is
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Question 8

A small mass m attached to one end of a spring with a negligible mass and an unstretched length L, executes vertical oscillations with angular frequency ω₀. When the mass is rotated with an angular speed (ω) by holding the other end of the spring at a fixed point, the mass moves uniformly in a circular path in a horizontal plane. Then the increase in length of the spring during this rotation is

Question 9

A particle of mass m is attached to three identical massless springs of spring constant k as shown in the figure. The time period of vertical oscillation of the particles is

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Question 10

A spring of force constant k is cut into three equal part force constant of each part would be

Question 11

Buna-S and Buna-N are the examples of _______ type of polymer.

Question 12

Find the correct statement among the following.

Question 13

The backbone of DNA is:

Question 14

To which of the following does thymine form hydrogen bonds in DNA?

Question 15

To which of the following does guanine form hydrogen bonds in DNA?

Question 16

The term is used to describe the process by which DNA is copied to produce two daughter DNA molecules is

Question 17

To form 1 mole of osazone of fructose. The number of moles of phenyl hydrazine required are

Question 18

Lactose is composed of-

Question 19

The compounds shown in the figure are related as

Question 20

Specify the IUPAC name of the compound shown:

Question 21

Let f(x) = sinx + 2cos²x, $Description: E:\WBJEE\2013\2013_Mathematics_files\image026.png$ ≤ x ≤ $Description: E:\WBJEE\2013\2013_Mathematics_files\image232.png$ . Then f attains its