Two masses m1 & m2 are initially at rest and are separated by a very large distance. If the masses approach each other subsequently, due to gravitational attraction between them, their relative velocity of approach at a separation distance of d is
A man of mass m starts falling towards a planet of mass M and radius R. As he reaches near to the surface, he realizes that he will pass through a small hole in the planet. As he enters the hole, he sees that the planet is really made of two pieces a spherical shell of negligible thickness of mass 2M/3 and a point mass M/3 at the centre. Change in the force of gravity experienced by the man is
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A spherical uniform planet is rotating about its axis. The velocity of a point on its equator is V. Due to the rotation of planet about its axis the acceleration due to gravity g at equator is 1/2 of g at poles. The escape velocity of a particle on the pole of planet in terms of V.
In the case of real gases, the equation of state, PV = RT (where P, V and T are respectively the pressure, volume and absolute temperature), is strictly satisfied only if corrections are applied to the measured pressure P and the measured volume V. The corrections for P and V arise respectively due to
Which one of the following quantities can be zero on an average for the molecules of an ideal gas in equilibrium?
One mole of any substance at any temperature, pressure or volume always contains ________ molecules.
Which diagram is the best depiction of the direction of flow of diffusion?
When two light nuclei combine to form a heavier nucleus, process is said to be
The elements of group 14 are slightly more electronegative than group 13 elements because of
In which of the following compounds, nitrogen exhibits highest oxidation state?
A compound X, of boron reacts with NH3 on heating to give another compound. Y which is called inorganic benzene. The compound X can be prepared by treating BF3 with Lithium aluminium hydride. The compounds X and Y are represented by the formulas.
Three reactions involving are given below
B.
C.
In which of the above does act as an acid?
When Cl2 gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): An apomixis is a form of asexual reproduction that mimics sexual reproduction.
Reason (R): There is no fertilisation in apomicts plants and they do not produce any seeds.
In the given diagram:
Statement I:I shows the entry of the pollen tube into a synergid under the guidance of A.
Statement II:II shows the discharge of male gametes into a synergid.
Endosperm type in which first division of primary endosperm nucleus and few subsequent division are not accompanied by wall formation is called?
Seminal plasma, the fluid part of semen is contributed by:
(i) Seminal vesicle
(ii) Prostate
(iii) Urethra
(iv) Bulbourethral gland
The testes are situated outside the abdominal cavity within a pouch called scrotum. This is necessary as:
Given below is a diagrammatic sketch of a portion of human male reproductive system. Select the correct set of the names of the parts labelled A, B, C, D:
Periodic abstinence is a natural method of contraception where the couples avoid or abstain from coitus during the period of the menstrual cycle when:
Diaphragms are contraceptive devices used by females. Choose the correct option from the statements given below:
(i) They are introduced into the uterus.
(ii) They are placed to cover the cervical region.
(iii) They act as physical barriers for sperm entry.
(iv) They act as spermicidal agents.
Statement I: Oral contraceptive pills are a safeguard against AIDS and sexual diseases besides checking pregnancy.
Statement II: Copper-T is a physical barrier preventing the body fluid of two partners to come in contact.
Which one of the following is the most widely accepted method of contraception in India at present?