A radioactive nucleus emits a beta particle. The parent and daughter nuclei are

When a β-particle is emitted from a nucleus then its neutron-proton ratio

The ionisation energy of hydrogen atom is 13.6 eV. Following Bohr's theory the energy corresponding to a transition between 3^rd and 4^th orbits is

A proton, a neutron, an electron and an a-particle have same energy. Then their de Broglie wavelengths compare as

A 220 V AC supply is connected between points A and B (figure). What will be the potential difference V across the capacitor?

 

A sample of a radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

After how many days will \(\frac { 1 }{ 20 } th\) of the radio active element remain behind, if half life of the element is 6.931 days

Given that light of wavelength 10,000 \(\overset { \circ }{ A } \)has an energy equal to 1.23eV. When light of wavelength 5000\(\overset { \circ }{ A } \) and intensity I₀ falls on a photosensitive plate  of photocell, the saturation current is \(0.43\times { 10 }^{ -6 }A\) and the stopping potential is 1.36V Then the work function is

Monochromatic light of frequency f₁ incident on a photocell and the stopping potential is found to be V₁. What is the new stopping potential of the cell if it radiated by monochromatic light of frequency f₂?

A p-type semiconductor is obtained by doping silicon with

A silicon p-n junction diode is connected to a resistor R and a battery of voltage V_B through milliammeter (mA) as shown in figure. The knee voltage for this junction diode is V_N = 0.7 V. The p-n junction diode requires a minimum current of 1m. A to attain a value higher than the knee point on the J- V characteristics of this junction diode. Assuming that the voltage V across the junction is independent of the current above the knee point. A p-n junction is the basic building block of many semiconductor devices like diodes. Important process occurring during the formation of a p-n junction are diffusion and drift. In an n-type semiconductor concentration of electrons is more as compared to holes. In a p-type semiconductor concentration of holes is more as compared to electrons.

(i) If V_B = 5 V, the maximum value of R so that the voltage V is above the knee point voltage is

(a) 40 \(\Omega\)

(b) 4.3 \(\Omega\)

(c) 5.0 \(\Omega\)

(d) 5.7 \(\Omega\)

(ii) If V_B = 5 V, the value of R in order to establish a current to 6 mA in the circuit is

(a) 833 \(\Omega\)

(b) 717 \(\Omega\)

(c) 950 \(\Omega\)

(d) 733 \(\Omega\)

(iii) If V_B = 6 V, the power dissipated in the resistor R, when a current of 6 mA flows in the circuit is

(a) 30.2 mW

(b) 30.8 mW

(c) 31.2 mW

(d) 31.8 mW

(iv) When the diode is reverse biased with a voltage of 6 V and V_bi = 0.63 V. Calculate the total potential.

(a) 9.27 V

(b) 6.63 V

(c) 5.27 V

(d) 0.63 V

(v) Which of the below mentioned statement is false regarding a p-n junction diode?

(a) Diodes are uncontrolled devices.	(b) Diodes are rectifying devices.
(c) Diodes are unidirectional devices.	(d) Diodes have three terminals

The nucleus was first discovered in 1911 by Lord Rutherford and his associates by experiments on scattering of a-particles by atoms. He found that the scattering results could be explained, if atoms consist of a small, central, massive and positive core surrounded by orbiting electrons. The experimental results indicated that the size of the nucleus is of the order of 10^-14m and is thus 10000 times smaller than the size of atom.
(i) Ratio of mass of nucleus with mass of atom is approximately

(a) 1

(b) 10

(c) 103

(d) 1010

(ii) Masses of nuclei of hydrogen, deuterium and tritium are in ratio

(a) 1:2:3

(b) 1:1:1

(c) 1:1:2

(d) 1:2:4

(iii) Nuclides with same neutron number but different atomic number are

(a) isobars

(b) isotopes

(c) isotones

(d) none of these

(iv) If R is the radius and A is the mass number, then log R versus log A graph will be

(a) a straight line

(b) aparabola

(c) anellipse

(d) none of these

(v) The ratio of the nuclear radii of the gold isotope \({ }_{79}^{197} \mathrm{Au}\) and silver isotope \({ }_{47}^{107} \mathrm{Au}\) is

(a) 1.23

(b) 0.216

(c) 2.13

(d) 3.46

The spectral series of hydrogen atom were accounted for by Bohr using the relation \(\bar{v}=R\left(\frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}}\right)\), 
where R = Rydberg constant = 1.097 x 10⁷ m.
Lyman series is obtained when an electron jumps to first orbit from any subsequent orbit. Similarly, Balmer series is obtained when an electron jumps to 2^nd orbit from any subsequent orbit, Paschen series is obtained when an electron jumps to 3^rd orbit from any subsequent orbit. Whereas Lyman series lies in U.V. region, Balmer series is in visible region and Paschen series lies in infrared region. Series limit is obtained when n₂ = \(\infty\)
(i) The wavelength of first spectral line of Lyman series is

(a) 1215.4 \(\dot A\)

(b) 1215.4 crn

(c) 1215.4 m

(d) 1215.4 mm

(ii) The wavelength limit of Lyman series is

(a) 1215.4 \(\dot A\)

(b) 511.9 \(\dot A\)

(c) 951.6 \(\dot A\)

(d) 911.6 \(\dot A\)

(iii) The frequency of first spectral line of Balmer series is

(a) 1.097 x 107 Hz

(b) 4.57 x 1014 Hz

(c) 4.57 x 1015 Hz

(d) 4.57 x 1016 Hz

(iv) Which of the following transitions in hydrogen atoms emit photons of highest frequency?

(a) n = 1 to n = 2

(b) n = 2 to n = 6

(c) n = 6 to n = 2

(d) n = 2 to n = 1

(v) The ratio of minimum to maximum wavelength in Balmer series is

(a) 5:9

(b) 5:36

(c) 1:4

(d) 3: 4

The photon picture of electromagnetic radiations and the characteristic properties of photons are as follows:In the interaction of radiation with matter, radiation behaves as if it is made of particles like photons. Each photon has energy \(E(=h v=h c / \lambda)\) and momentum \(p\left(=\frac{h v}{c}=\frac{h}{\lambda}\right)\) where h is Planck's constant, v and A are the frequency and wavelength of radiation and c is the velocity of light. The photon energy is independent of the intensity of radiations. All the photons emitted from a source of radiations travel through space with the same speed c. The frequency of photon gives the radiation, a definite energy (or colour) which does not change when photon travels through different media. Photons are not deflected by electric and magnetic fields. This shows that photons are electrically neutral.
(i) Which one among the following shows particle nature of light?

(a) Photoelectric effect

(b) Interference

(c) Refraction

(d) Polarization

(ii) Which of the following statements about photon is incorrect?

(a) Photons exert no pressure	(b) Momentum of photon is \(\frac{h v}{c}\)
(c) Rest mass of photon is zero	(d) Energy of photon is hv

(iii) The rest mass of photon is

\(\text { (a) } \frac{h v}{c}\)

\(\text { (b) } \frac{h v}{c^{2}}\)

\(\text { (c) } \frac{h v}{\lambda}\)

(d) zero

(iv) In a photon-particle collision (such as photon-electron collision), which of the following may not be conserved?

(a) Total energy

(b) Number of photons

(c) Total momentum

(d) Both (a) and (b)

(v) 'n' photons of wavelengt '\(\lambda\)' are absorbed by a black body of mass 'm'. The momentum gained by the body is

\(\text { (a) } \frac{h}{m \lambda}\)

\(\text { (b) } \frac{m n h}{\lambda}\)

\(\text { (c) } \frac{n h}{m \lambda}\)

\(\text { (d) } \frac{n h}{\lambda}\)

Assertion (A): A p-n junction diode conducts current in the forward bias but not in the reverse bias.
Reason (R): In forward bias, the p-n junction allows the flow of majority carriers, facilitating current flow, while in reverse bias, the depletion region widens, preventing current flow.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion (A) : The ratio of free electrons to holes in intrinsic semiconductor is greater than one.
Reason (R) : The electrons are lighter particles and holes are heavy particles.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion (A): The Heisenberg uncertainty principle states that it is impossible to simultaneously determine the exact position and momentum of an electron.
Reason (R): The act of measurement of position and momentum of an electron disturbs the electron’s state, making it impossible to know both properties with certainty.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion : The stopping potential in the photoelectric effect is independent of the intensity of incident light.
Reason : The stopping potential depends only on the frequency of incident light, which determines the energy of photons.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion (A): The Rydberg formula can be used to calculate the wavelengths of spectral lines in hydrogen-like atoms.
Reason (R): The Rydberg formula is based on the energy levels of the electron in the hydrogen atom.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion : The ionising power of β-particle is less compared to β-particles but their penetrating power is more.
Reason : The mass of β-particle is less than the mass of α- particle.
Codes:
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.

Assertion (A) : Two protons can attract each other.
Reason (R) : The distance between the protons within the nucleus is about 10^–15 m.
Codes:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.

Assertion (A) : The resistivity of a semiconductor increases with temperature.
Reason (R) : The atoms of a semiconductor vibrate with larger amplitude at higher temperatures thereby increasing its resistivity.
Codes:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false

Assertion (A) : Laser is used to measure distant object like moon.
Reason (R) : They are highly coherent source of light
Codes:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false

Assertion (A) : Stopping potential depends upon the frequency of incident light but is independent of the intensity of the light.
Reason (R) : The maximum kinetic energy of the photoelectrons is proportional to stopping potential.
Codes:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false