List of practice Questions

A charged particle of charge Q arid mass m moves with velocity v in a circular path due to transverse magnetic field, B, then its frequency is
A charged oil drop is suspended in uniform field of $3 \times 10^4\, V/m$ so that it neither falls nor rises. The charge on the drop will be (Take the mass of the charge $= 9.9 \times 10^{-15}\, kg$ and $g = 10\, m/s^2)$
A certain radioactive substance has a half-life of 5 years. Thus for a nucleus in a sample of the element, the probability of decay in ten years is
A chain reaction in fission of Uranium is possible because
A certain compound $X$ imparts a golden yellow flame. When zinc powder is heated with concentrated solution of $X$, $H_2$ gas is evolved. $X$ combines with $CO_2$ to give a salt $Y$. $Y$ is a hydrated salt which on reaction with $HCl$ or excess of $CO_2$ gives another salt $Z$ which is an important part of baking powder. Identify $X$, $Y$ and $Z$.
A certain current liberate 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution ?
A certain compound has a formula $ {C_3H_6O}$. It combines with hydroxylamine to form two compounds which are geometrical isomers of each other. It is
A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of 140?. The fall of temperature as registered by the Centigrade thermometer is:
Phloem sap contains
When a plant part undergoes sensence, the nurients may be
In contact with moisture dry cobalt chloride paper turns
In guard cells, starch gets hydrolysed under condition of
Opening of stomata requires
Who proved that upward transport of minerals occurs through xylem
A cell's division time is $1$ minute. In $20$ minutes, a culture tube (culture medium) is $1/8^{th}$ filled with cells. When the tube will be fully filled?
Imbibition pressure develops due to
Units of water transpired by a plant for synthesis of one unit of dry matter is called
A cart is moving horizontally along a straight line with constant speed 30 m/s. A projectile is to be fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (Relative to the cart) must the projectiie be fired? (Take g = $ 10 \, ms^{ - 2} $ )
A cavity of radius $\frac{R}{2}$ is made inside a solid sphere of radius R . The center of the cavity is located at a distance $\frac{r}{2}$ from the center of sphere. The gravitational force on a particle of mass m at a distance $\frac{R}{2}$ from the center of the sphere on the line joining both the centers of sphere and cavity is ( opposite to the center of cavity ) [ here $g=\frac{GM}{R^2}$ where M the mass of the sphere ].
A card from a pack of $52$ cards is lost. From the remaining cards of the pack, two cards are drawn and are found to be both clubs. Find the probability of the lost card being a club.
A card is drawn from a well-shuffled deck of $52$ cards. Find the odds in favour of getting a face card.
A car starts from rest and travels with uniform acceleration $\alpha$ for some time and then With uniform retardation $\beta$ and comes to rest If the total time of travel of the car is 't' the maximum velocity attained by it is given by
A car travels first half distance between the places with a speed of $30\, km \,h^{-1}$ and remaining half with a speed of $50\, km \, h^{-1}$. The average speed of car is
A car weighs $1800 \,kg$. The distance between its front and back axles is $1.8 \,m$. Its centre of gravity is $1 \,m$ behind the front axle. The force exerted by the level ground on each front wheel and each back wheel is (Take $g = 10\, m s^{-2})$
A card, drawn at random from a pack of 52 cards, is noted and kept aside. Another card is then drawn from the remaining pack at random. The probability that both the cards are kings is