JEE Mains Physics 2002-2019 Solved Video Solutions
Hydrogen atom in its ground state is excited by means of monochromatic radiation of wavelength 975 A ∘. How many different lines are possible in the resulting spectrum? Calculate the longest wavelength amongst them. You may assume the ionization energy for hydrogen atom as 13.6 eV.
16
Sep
Hydrogen atom in its ground state is excited by means of monochromatic radiation of wavelength 975 A ∘. How many different lines are possible in the resulting spectrum? Calculate the longest wavelength amongst them. You may assume the ionization energy for hydrogen atom as 13.6 eV. Beta rays emitted by a radioactive material are. September [...]
A single electron orbits around a stationary nucleus of charge +Ze, where Z is a constant and e is the magnitude of the electronic charge. It requires 47,2 eV to excite the electron from the second Bohr orbit to the third Bohr orbit. Find
16
Sep
A single electron orbits around a stationary nucleus of charge +Ze, where Z is a constant and e is the magnitude of the electronic charge. It requires 47,2 eV to excite the electron from the second Bohr orbit to the third Bohr orbit. Find 2 eV to excite the electron from the second Bohr orbit [...]
In a photoelectric experiment a parallel beam of monochromatic light with power of 200 W is incident on a perfectly absorbing cathode of work function 6.25 eV. The frequency of light is just above the threshold frequency so that the photoelectrons are emitted with negligible kinetic energy. Assume that the photoelectron emission efficiency is 100% A potential difference of 500 V is applied between the cathode and the anode. All the emitted electrons are incident normally on the anode and are absorbed. The anode experiences a force F = n ×10^–4N due to the impact of the electrons. The value of n is…….. Mass of the electron me = 9 × 10–31kg and 1.0eV = 1.6 × 10^–19J.?
16
Sep
In a photoelectric experiment a parallel beam of monochromatic light with power of 200 W is incident on a perfectly absorbing cathode of work function 6.25 eV. The frequency of light is just above the threshold frequency so that the photoelectrons are emitted with negligible kinetic energy. Assume that the photoelectron emission efficiency is 100% [...]
For a radioactive material, its activity A and rate of change of its activity R are defined as A = − dt/dN and R = − dt/dA , where N(t) is the number of nuclei at time t. Two radioactive sources P(mean life τ) and Q (mean life 2τ) have the same activity at t = 0. Their rates of change of activities at t = 2τ are RP and RQ, respectively. If RQ/RP = e/n , then the value of n is
16
Sep
For a radioactive material, its activity A and rate of change of its activity R are defined as A = − dt/dN and R = − dt/dA , where N(t) is the number of nuclei at time t. Two radioactive sources P(mean life τ) and Q (mean life 2τ) have the same activity at [...]
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For a radioactive material ,
its activity A and rate of change of its activity R are defined as A = − dt/dN and R = − dt/dA ,
respectively. If RQ/RP = e/n ,
then the value of n is ,
where N(t) is the number of nuclei at time t. Two radioactive sources P(mean life τ) and Q (mean life 2τ) have the same activity at t = 0. Their rates of change of activities at t = 2τ are RP and RQ ,
131I is an isotope of Iodine that B decays to an isotope of Xenon with a half-life of 8 days. A small amount of a serum labelled with 131I is injected into the blood of a person. The activity of the amount of 131I injected was 2.4 × 10^5 Becquerel (Bq). It is known that the injected serum will get distributed uniformly in the blood stream in less than half an hour. After 11.5 hours, 2.5 ml of blood is drawn from person’s body, and gives an activity of 115 Bq. The total volume of blood in the person’s body, in liters is approximately (you may use e^x ≈1 + x for |x| < < 1 and ln2 ≈ 0.7).
16
Sep
131I is an isotope of Iodine that B decays to an isotope of Xenon with a half-life of 8 days. A small amount of a serum labelled with 131I is injected into the blood of a person. The activity of the amount of 131I injected was 2.4 × 10^5 Becquerel (Bq). It is known that [...]
A nuclear power planet supplying electrical power to a village uses a radioactive material of half life T years as the fuel. The amount of fuel at the beginning is such that the total power requirement of the village is 12.5% of the electrical power available from the plant at that time. If the plant is able to meet the total power needs of the village for a maximum period of n T years, then the value of n is.
16
Sep
A nuclear power planet supplying electrical power to a village uses a radioactive material of half life T years as the fuel. The amount of fuel at the beginning is such that the total power requirement of the village is 12.5% of the electrical power available from the plant at that time. If the plant [...]
A freshly prepared sample of a radioisotopes of half-life 1386s has activity 10^3 disintegrations per second. Given that ln 2 = 0.693, the fraction of the initial number of nuclei (expressed in nearest percentage) that will decay in the first 80s after preparation of the sample is
16
Sep
A freshly prepared sample of a radioisotopes of half-life 1386s has activity 10^3 disintegrations per second. Given that ln 2 = 0.693, the fraction of the initial number of nuclei (expressed in nearest percentage) that will decay in the first 80s after preparation of the sample is A freshly prepared sample of a radioisotopes of [...]
The activity of a freshly prepared radioactive sample is 10^10 disintegrations per second, whose mean life is 10^9 s. The mass of an atom of this radioisotopes is 10^-25 kg. The mass (in mg) of the radioactive sample is
16
Sep
The activity of a freshly prepared radioactive sample is 10^10 disintegrations per second, whose mean life is 10^9 s. The mass of an atom of this radioisotopes is 10^-25 kg. The mass (in mg) of the radioactive sample is The activity of a freshly prepared radioactive sample is 10^10 disintegrations per second whose mean life [...]
The radius of the orbit of an electron in a Hydrogen-like atom is 4.5 a0 where a0 is the Bohr radius. Its orbital angular momentum is 3h/2π It is given that h is Planck constant and R is Rydberg constant. The possible wavelength(s), when the atom de-excites, is (are)
15
Sep
The radius of the orbit of an electron in a Hydrogen-like atom is 4.5 a0 where a0 is the Bohr radius. Its orbital angular momentum is 3h/2π It is given that h is Planck constant and R is Rydberg constant. The possible wavelength(s), when the atom de-excites, is (are) Beta rays emitted by a radioactive [...]
If the wavelength of the n^(th) line of Lyman series is equal to the de-Broglie wavelength of electron in initial orbit of a hydrogen like element (Z=11). Find the value of n.
15
Sep
If the wavelength of the n^(th) line of Lyman series is equal to the de-Broglie wavelength of electron in initial orbit of a hydrogen like element (Z=11). Find the value of n. If the wavelength of the n^(th) line of Lyman series is equal to the de-Broglie wavelength of electron in initial orbit of a [...]