Propose two conservation measures that could be taken to increase the number of lions in Gir forest.

Propose two conservation measures that could be taken to incerease the number of Indian one-horned rhino.Make your opinion based on your experiences how the sources of fresh water became polluted.

Write down two reservation process to increase the number of one horned rhino in Jaldapara.

What is the cause of decreasing number of lion? How it can be conserved?

Species very near to extinction if conservation measures are not promptly taken is (a) Threatened species (b) Rare species (c) Endangered species (d) Vulnerable species

Write the in situ conservation measures taken for one endangered reptile speies and name one site of such conservation in West Bengal.

What do you mean by conservation of mass number and atomic number ? Show that from it two displacement laws of alpha and beta -decay can be obtained from these conservation laws .

From the two arms of a beam balance, a metal body weighing 20 g and a piece of glass are suspended. The apparent weights of these two bodies when measured in water are found to be the same. If immersed in alcohol instead of water, the mass of the metal needs to be increased by 0.84 g for balancing the beam. Calculate the mass of the glass piece. [Given, density of water = 1g*cm^(-3) , density of alcohol = 0.96g*cm^(-3) ]

Write two differences between In-situ and Ex-situ conservation. Explain how JFM contributes to the recovery of destroyed forest.

Two tuning forks, vibrating simultaneously, produce 6 beats per second. The first of them has a frequency of 312 Hz . Some amount of wax is added to one arm of the second tuning fork , the number of beats per second reduces to 3 . Find out the frequency of this second tuning fork . Is it possible to increase the beat frequency to 6 per second by adding some more wax to the second tuning fork ?

Einstein established the idea of photons on the basis of Planck's quantum theory. According to his idea, the light of frequency f or wavelength lamda is infact a stream of photons. The rest mass of each photon is zero and velocity is equal to the velocity of light (c) = 3 xx 10^(8) m.s^(-1) . Energy, E = hf, where h = Planck's constant = 6.625 xx 10^(-34)J.s . Each photon has a momentum p = (hf)/(c) , although its rest mass is zero. The number of photons increase when the intensity of incident light increases and vice-versa. On the other hand, according to de Broglie any stream of moving particles may be represented by progressive waves. The wavelength of the wave (de Broglie wavelength) is lamda = (h)/(p) , where p is the momentum of the particle. When a particle having charge e is accelerated with a potential difference of V, the kinetic energy gained by the particle is K= eV. Thus as the applied potential difference is increased, the kinetic energy of the particle and hence the momentum increase resulting in a decrease in the de Broglie wavelength. Given, charge of electron, e = 1.6 xx 10^(-19)C and mass = 9.1 xx 10^(-31) kg . Two stationary electrons are accelerated with potential difference V_(1) and V_(2) respectively such that V_(1) : V_(2) = n . The ratio of their de Broglie wavelength