List of practice Questions

The following statements concern elements in the periodic table. Which of the following is true ?

Decomposition of $H_2O_2$ follows a first order reaction. In fifty minutes the concentration of $H_2O_2$ decreases from $0.5$ to $0.125 \,M$ in one such decomposition. When the concentration of $H_2O_2$ reaches $0.05 \,M$, the rate of formation of $O_2$ will be :

Extraction of copper by smelting uses silica as an additive to remove :

Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum Arabic : 0.15 - 0.25; Oleate : 0.04 - 1.0; Starch : 15 - 25. Which among these is a better protective colloid ?

Identify the incorrect statement regarding heavy water :

Which of the following is an anionic detergent?

A Carnot freezer takes heat from water at $0^{\circ}C$ inside it and rejects it to the room at a temperature of $27^{\circ}C$. The latent heat of ice is $336 \times 10^3 J \, kg^{-1}$. If $5\, kg$ of water at $0^{\circ}C$ is converted into ice at $0^{\circ}C$ by the freezer, then the energy consumed by the freezer is close to :

Identify the reaction which does not liberate hydrogen :

An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity Cremains constant. If during this process the relation of pressure $P$ and volume $V$ is given by $PV^n =$ constant, then $n$ is given by (Here $C_P$ and $C_V$ are molar specific heat at constant pressure and constant volume, respectively) :

Radiation of wavelength $\lambda$, is incident on a photocell. The fastest emitted electron has speed $v$. If the wavelength is changed to $\frac{3 \lambda}{4}$, the speed of the fastest emitted electron will be :

Half-lives of two radioactive elements $A$ and $B$ are $20\, $ minutes and $40\,$ minutes, respectively. Initially, the samples have equal number of nuclei. After $80\,$ minutes, the ratio of decayed numbers of $A$ and $B$ nuclei will be :

To know the resistance $G$ of a galvanometer by half deflection method, a battery of emf $V_E$ and resistance $R$ is used to deflect the galvanometer by angle $\theta$. If a shunt of resistance $S$ is needed to get half deflection then $G, R$ and $S$ are related by the equation :

Bouveault-Blanc reduction reaction involves :

Two wires having same length and material are stretched by same force. Their diameters are in the ratio $1 : 3$. The ratio of strain energy per unit volume for these two wires (smaller to larger diameter) when stretched is

If the current in the toroidal solenoid increases uniformly from zero to $6.0\, A$ in $3.0?s.$ Self inductance of the toroidal solenoid is $40?H$. The magnitude of self induced emf is

The fruit of coconut is:

When rigid body has neither linear acceleration nor angular acceleration then it is said to be in

A battery of constant voltage is available. How to adjust a system of three identical capacitors to get high electrostatic energy with the given battery

In vertical circular motion, the ratio of kinetic energy of a particle at highest point to that at lowest point is

A ring and a disc roll on the horizontal surface without slipping with same linear velocity. If both have same mass and total kinetic energy of the ring is $4\, J$ then total kinetic energy of the disc is

Direction cosines of the line $\frac{x+2}{2} = \frac{2y-5}{3}, z = -1$ is

Edible fungus is:

The current flowing through the 3$\Omega$ resistor in the circuit is,