List of practice Questions

Three point charges, each of charge \( q \), are placed on vertices of a triangle \( ABC \), with \( AB = AC = 5L \), \( BC = 6L \). The electrostatic potential at the midpoint of side \( BC \) will be:
The de Broglie wavelength of an electron with kinetic energy of \( 2.5 \) eV is (in m): \[ (1 \text{ eV} = 1.6 \times 10^{-19} \text{ J}, \quad m_e = 9 \times 10^{-31} \text{ kg}) \]
An organic compound contains carbon = 38.71%, Hydrogen = 9.67% and Oxygen. The empirical formula of the compound would be:
Which of the following statement (s) is (are) true about human heart?
(a) Right atrium receives oxygenated blood from lungs through pulmonary artery.
(b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body.
(c) Right atrium receives deoxygenated blood from different parts of the body through vena cava.
(d) Left atrium transfers oxygenated blood to aorta which sends it to different parts of the body.
A cross between two tall pea plants resulted in offspring having a few dwarf plants. The gene-combination of the parental plants must be
The phenomena of light involved in the formation of a rainbow in the sky are
In case of four wires of same material, the resistance will be minimum if the diameter and length of the wire respectively are
A food chain will be more advantageous in terms of energy if it has
Consider the following statements about ozone :
(a) Ozone is poisonous gas.
(b)Ozone shields the earth's surface from the infrared radiation from the sun.
(c) Ozone is a product of UV radiations acting on oxygen molecule.
(d) At the lower level of the earth's atmosphere, ozone performs most essential function.
The correct statements are
Assertion (A) : A piece of Zinc metal gets reddish brown coating when kept in copper sulphate solution for some time.
Reason (R) : Copper is more reactive metal than Zinc.
Assertion (A): Offsprings produced by asexual reproduction are genetically similar to the parents.
Reason (R): Asexual reproduction involves a single parent.
Assertion (A): Red light signals are used to stop the vehicles on the road.
Reason (R): Red coloured light is scattered the most so as to be visible from a large distance.
Assertion (A): The waste we generate daily may be biodegradable or non-biodegradable.
Reason (R): The waste generated, if not disposed off properly may cause serious environmental problems.
When magnesium ribbon is burnt in air, an ash of white colour is produced. Write chemical equation for the reaction giving the chemical name of the ash produced. State the type of chemical reaction giving justification for your answer.
Where are auxins synthesized? How do they promote phototropism?
List any two pairs of visible contrasting characters of garden pea plants used by Mendel for his experiments stating the dominant and recessive characters in each pair.
In human beings, the probability of getting a male or a female child is 50%. Explain with the help of a flow diagram only.
When do we say that a particular person is suffering from hypermetropia? List two causes of this defect. Name the type of lens used to correct this defect.
Draw a labelled diagram to show the pattern of magnetic field lines produced due to a current carrying straight conductor. Mark on it the direction of current in the conductor and the direction of magnetic field lines.
Name the device used to magnetise a piece of magnetic material. Draw a labelled diagram to show the arrangement used for the magnetisation of a cylinder made of soft iron.
What are decomposers? List two consequences of their absence in an ecosystem.
State reasons for the following:
(a) Zinc oxide is an amphoteric oxide.
(b) Sodium metal is stored in bottle filled with kerosene oil.
(c) In the reactions of nitric acid with metals, generally hydrogen gas is not evolved.
State giving reason the reduction process to obtain the following metals from their compounds:
(i) Mercury,
(ii) Copper and
(iii) Sodium
State giving reason for the change in appearance observed when each of the following metal is exposed to atmospheric air for some time:
(i) Silver,
(ii) Copper and
(iii) Iron
We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.