The power radiated from a linear antenna of length $$l$$ is proportional to (Given, $$\lambda =$$ Wavelength of wave):

A TV transmitting antenna is $$98\mathrm{m}$$ high and the receiving antenna is at the ground level. If the radius of the earth is $$6400\mathrm{km}$$, the surface area covered by the transmitting antenna is approximately:

By what percentage will the transmission range of a TV tower be affected when the height of the tower is increased by $$21\%$$ ?

For an amplitude modulated wave the minimum amplitude is $$3\mathrm{V}$$, while the modulation index is $$60\%$$. The maximum amplitude of the modulated wave is:

An electron of a hydrogen like atom, having $$Z=4$$, jumps from $$4^{\text{th }}$$ energy state to $$2^{\text{nd }}$$ energy state. The energy released in this process, will be : (Given Rch = $$13.6\mathrm{eV}$$) Where R = Rydberg constant c = Speed of light in vacuum h = Planck's constant

The radius of electron's second stationary orbit in Bohr's atom is R. The radius of 3rd orbit will be

The mass of proton, neutron and helium nucleus are respectively $$1.0073u,1.0087u$$ and $$4.0015u$$. The binding energy of helium nucleus is :

A free neutron decays into a proton but a free proton does not decay into neutron. This is because

Given below are two statements: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$ Assertion A: The nuclear density of nuclides ${}_5^{10}\mathrm{B},{}_3^6\mathrm{Li},{}_{26}^{56}\mathrm{Fe},{}_{10}^{20}\mathrm{Ne}$ and ${}_{83}^{209}\mathrm{Bi}$ can be arranged as ${\rho }_{\mathrm{Bi}}^{\mathrm{N}}>{\rho }_{\mathrm{Fe}}^{\mathrm{N}}>{\rho }_{\mathrm{Ne}}^{\mathrm{N}}>{\rho }_{\mathrm{B}}^{\mathrm{N}}>{\rho }_{\mathrm{Li}}^{\mathrm{N}}$ Reason R: The radius $R$ of nucleus is related to its mass number $A$ as $R=R_0{A}^{1/3}$, where $R_0$ is a constant. In the light of the above statements, choose the correct answer from the options given below

Speed of an electron in Bohr's $$7^{\text{th }}$$ orbit for Hydrogen atom is $$3.6\times 10^6\mathrm{m}/\mathrm{s}$$. The corresponding speed of the electron in $$3^{\text{rd }}$$ orbit, in $$\mathrm{m}/\mathrm{s}$$ is :

Substance A has atomic mass number 16 and half life of 1 day. Another substance B has atomic mass number 32 and half life of $$\frac{1}{2}$$ day. If both A and B simultaneously start undergo radio activity at the same time with initial mass 320 g each, how many total atoms of A and B combined would be left after 2 days.

If a radioactive element having half-life of $$30\min$$ is undergoing beta decay, the fraction of radioactive element remains undecayed after $$90\min$$. will be

The energy levels of an atom is shown in figure. Which one of these transitions will result in the emission of a photon of wavelength 124.1 nm? Given (h = 6.62 $$\times$$ 10$${}^{-34}$$ Js)

The ratio of the density of oxygen nucleus ($${}_8^{16}O$$) and helium nucleus ($${}_2^4\mathrm{He}$$) is

A photon is emitted in transition from n = 4 to n = 1 level in hydrogen atom. The corresponding wavelength for this transition is (given, h = 4 $$\times$$ 10$${}^{-15}$$ eVs) :

Consider the following radioactive decay process $${}_{84}^{218}A\text{buildrel}\alpha \frac{⟶}{A_1}\text{buildrel}{\beta }^{-}\frac{⟶}{A_2}\text{buildrel}\gamma \frac{⟶}{A_3}\text{buildrel}\alpha \frac{⟶}{A_4}\text{buildrel}{\beta }^{+}\frac{⟶}{A_5}\text{buildrel}\gamma \frac{⟶}{A_6}$$ The mass number and the atomic number of A$${}_6$$ are given by :

The half-life of a radioactive nucleus is 5 years. The fraction of the original sample that would decay in 15 years is:

Given below are two statements: one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason $$\mathbf{R}$$ Assertion A : The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range 30 to 170 . Reason R : Nuclear force is short ranged. In the light of the above statements, choose the correct answer from the options given below

$${}_{92}^{238}A{\to }_{90}^{234}B{+}_2^{4}D+Q$$ In the given nuclear reaction, the approximate amount of energy released will be: [Given, mass of $${}_{92}^{238}\mathrm{A}=238.05079\times 931.5\mathrm{MeV}/{\mathrm{c}}^2,$$ mass of $${}_{90}^{234}B=234\cdot 04363\times 931\cdot 5\mathrm{MeV}/{\mathrm{c}}^2,$$ mass of $${}_2^{4}D=4\cdot 00260\times 931\cdot 5\mathrm{MeV}/{\mathrm{c}}^2]$$

A $$12.5\mathrm{eV}$$ electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be: