List of top Questions asked in OJEE

A true solution does not show Tyndall effect, because of the:
The solvent used to prepare aqueous solutions is:
A wave along a string has the following equation \( y = 0.02 \sin [30t – 4.0x] \) m. The speed of the wave is:
A wire 0.5 m long and with a mass per unit length of 0.0001 kg/m vibrates under a tension of 4 N. The fundamental frequency is:
How far should an object be from a concave spherical mirror of radius 36 cm to form a real image one-ninth its size?
A glass bulb of volume 400 cm\(^3\) is connected to another bulb of volume 200 cm\(^3\) by means of a tube of negligible volume. The bulbs contain dry air. They are both at a common temperature and pressure of 20°C and 1.000 atm. The larger bulb is immersed in steam at 100°C; the smaller, in melting ice at 0°C. The final common pressure is:
The amount of moisture that must evaporate from a 5.0 kg body to reduce its temperature by 2°C is \( m \) g. The heat of vaporization for water at body temperature is about 580 cal/g. The specific heat capacity for the body is 0.83 cal/g°C. The value of \( m \) is:
A sphere of 3 cm radius acts like a black body. It is in equilibrium with its surrounding and absorbs 30 kW of power radiated to it from surroundings. The temperature of the sphere is \( \sigma = 5.67 \times 10^{-8} \, \text{W/m}^2\text{K}^4 \). What is the temperature of the sphere?
A drop of water of radius 0.01 m is falling through a medium whose density is 1.21 kg/m\(^3\) and co-efficient of viscosity \( \eta = 1.8 \times 10^{-5} \, \text{Ns/m}^2 \). Then the terminal velocity of the drop is:
100 Vernier scale divisions match with 99 main scale divisions of a slide caliper. If the value of each main scale division is 1 mm, then the Vernier constant is:
At temperature 'T', the 'effective' speed of gaseous hydrogen molecules (molecular weight = 2) is equal to that of oxygen molecules (molecular weight = 32) at 47°C. The value of 'T' is:
A hole of area 1 mm\(^2\) opens in the pipe near the lower end of a large water storage tank, and a stream of water shoots from it. If the top of the water in the tank is 20 m above the point of the leak, the amount of water escapes in 1 s is:
Same quantity of ice is filled in each of the two identical metal containers P and Q having the same size and shape but of different materials. In P ice melts completely in time \( t_1 \), whereas in Q the time taken is \( t_2 \). Then the ratio of conductivities of P and Q is:
The temperatures of two bodies differ by 1°C. How much will they differ on Fahrenheit scale?
One mole of helium gas, initially at STP (p₁ = 1 atm, T₁ = 0°C), undergoes an isovolumetric process in which its pressure falls to half its initial value. The work done by the gas is:
A charge \( q \) is placed at the centre of the line joining two equal charges \( Q \). The system of the three charges will be in equilibrium if \( q \) is equal to:
In a diesel engine, the cylinder compresses air from approximately standard pressure and temperature to about one-sixteenth the original volume and a pressure of about 50 atm. The temperature of the compressed air is:
From the measurement made on the Earth, it is known that the Sun has a surface area of \( 6.1 \times 10^{18} \) m\(^2\) and radiates energy at the rate of \( 3.9 \times 10^{26} \) W. Assuming that the emissivity of the Sun's surface is 1, the temperature of the Sun's surface is:
The velocity of a particular mass \( m \) is \( \vec{v} = 5 \hat{i} + 4 \hat{j} + 6 \hat{k} \) when at \( \vec{r} = -2 \hat{i} + 4 \hat{j} + 6 \hat{k} \). The angular momentum of the particle about the origin is:
The two wires A and B of the same material have their lengths in the ratio 1 : 2 and their diameters in the ratio 2 : 1. If they are stretched with the same force, the ratio of the increase in the length of A to that of B will be:
The increase in pressure required to decrease the volume of 200 L of water by 0.004 percent is (Bulk modulus of water is \( 2.1 \times 10^9 \) N/m\(^2\)):
The volume of an air bubble is doubled as it rises from the bottom of a lake to its surface. The atmospheric pressure is 75 cm of mercury and the ratio of the density of mercury to that of lake water is 40/3. The depth of the lake is:
Water is flowing through a tube of radius \( r \) with a speed \( v \). If this tube is joined to another tube of radius \( r/2 \), the speed of water in the second tube is:
One mole of an ideal gas is at temperature \( T \) K. The \( \gamma \) value of this gas is \( \frac{5}{3} \). Now the gas does 12R Joules of work adiabatically (R is the universal gas constant). Then the final temperature of the gas will be:
A light ladder is supported on a rough floor and leans against a smooth wall, touching the wall at height \( h \) above the floor. A man climbs up the ladder until the base of the ladder is on the verge of slipping. The coefficient of static friction between the foot of the ladder and the floor is \( \mu \). The horizontal distance moved by the man is: