List of practice Questions

A stone is dropped into a lake from a tower $500 \,m$ high. The sound of the splash will be heard by a man on the tower after: [Assume speed of sound $\left.=330\, m / s ; g =10 \,m / s ^{2}\right]$
In the case of a moving body, pick the correct statement
streamer moves with velocity $3 \,km \,h^{-1}$ in and against the direction of river water whose velocity is $2\, km\, h^{-1}$. Calculate its total time for total journey if the boat travels 2 km in direction of the stream and then back to his place.
Check up the only correct statement in the following
A bag contains n coupons marked 1, 2, 3, ........ n. If two coupons are drawn then the chance that the difference of the coupons exceeds m (less than n -1) is:
A ball A is dropped from a building of height $ 45\, m $ . Simultaneously another identical ball $ B $ is thrown up with a speed $ 50 \,m \,s^{-1} $ . The relative speed of ball $ B $ w.r.t. ball A at any instant of time is (Take $ g = 10\, m \,s^{-2}) $
A body is projected vertically upwards at time t = 0 and is seen at a height H at time $t_1$ and $t_2$ seconds during its flight. The maximum height attained is [g is acceleration due to gravity]
A bag contains $4$ balls. Two balls are drawn at random and are found to be white. What is the probability that all balls are white?
A bag contains $6$ red, $4$ blue and $2$ yellow balls. Three balls are drawn one by one with replacement. Find the probability of getting exactly one red ball.
A bag contains $6$ red, $5$ blue and $7$ white balls. If three balls are drawn one by one (without replacement), then what is the probability that all three balls are blue?
A bag contains $n$ balls. It is given that the probability that among these n balls exactly $r$ balls are white is proportional to $r^2 (0 \le r \le n)$. A ball is drawn at random and is found to be white. Then the probability that all the balls in the bag are white, will be:
A bag contains $12$ white pearls and $18$ black pearls. Two pearls are drawn in succession without replacement. Find the probability that the first pearl is white and the second is black.
A bag contains $20$ tickets, numbered $1$ to $20$. A ticket is drawn and then another ticket is drawn without replacement. Find the probability that both tickets will show even numbers.
Heterocysts are specialised for nitrogen fixation as they are
In cyanobacterial cell
Mineral extraction with the help of bacteria is
Ptomaines are
The common bacterium of boils which also causes food poisoning is
The most abundant microorganisms are,
A thermoacidophile of hot sulphur spring is
Anaerobic retting of fibres is carried out by
Red carotenoids help halophiles in
Copeland created the kingdom of
shrivelled face, sunken eye: prominent ribs, thin legs and aram are found in
Vomiting is controlled by