Download App

Atoms — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsAtoms1 Mark
Question
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is NOT the correct explanation of A.
  3. A is true, but R is false.
  4. A is false and R is also false.

Assertion (A): For the scattering of $\alpha$-partides at a large angles, only the nucleus of the atom is responsible.

Reason (R): Nucleus is very heavy in comparison to electrons.

✓

Answer

  1. Both A and R are true, and R is the correct explanation of A.

Explanation:

We know that an electron is very light particle as compared to an $\alpha$-particle. Hence, electron cannot scatter the $\alpha$-particle at large angles, according to law of conservation of momentum. On the other hand, mass of nucleus is comparable with the mass of $\alpha$-particle, hence only the nucleus of atom is responsible for scattering of $\alpha$-particles.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion (A) & Reason (B) MCQ" from Atoms→Atoms — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): A narrow pulse of light is sent through a medium. The pulse will retain its shape as it travels through the medium.
Reason (R): A narrow pulse is made of harmonic waves with a large range of wavelengths.
→
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): The interference pattem is observed when source is monochromatic and coherent.
Reason (R): In Young's double slit experiment, we observe an interference pattern on the screen if both the slits are illuminated by two bulbs of same power.
→
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from thecodes(a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion: In a semiconductor diode, the reverse biased current is due to drift of free electrons and holes.
Reason: The drift of electrons and holes is due to thermal excitation.
→
Directions: In the following questions, the Assertions (A) and Reason(s) (R) have been put forward. Read both the statements carefully and choose the correct alternative from the following:
Assertion: Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.
Reason: Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it.
  1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
  2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
  3. Assertion is correct but Reason is incorrect.
  4. Both Assertion and Reason are incorrect.
→
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): Range of Coulomb force is infinite.
Reason (R): Coulomb force acts between two charged particles.
→
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b ), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and Rare true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): Changing magnetic flux can produce induced e.m.f.
Reason (R): Faraday established induced e.m.f. experimentally.
→
For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): If a point charge be rotated in a circle around a charge, the work done will be zero.
Reason (R): Work done is equal to dot product of force and distance.
→
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion: A double convex lens $(\mu = 1.5)$ has focal length 10cm. When the lens is immersed in water $\big(\mu=\frac{4}{3}\big)$ its focal length becomes 78.24cm.
Reason: $\frac{1}{\text{f}}=\frac{\mu_\text{g}-\mu_\text{m}}{\mu_\text{m}}\Big(\frac{1}{\text{R}_1}-\frac{1}{\text{R}_2}\Big).$
→
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): A charged particle moving in a uniform magnetic field penetrates a layer of lead and there by loses half of its kinetic energy. The radius of curvature of its path is now reduced to half of its initial value.
Reason (R): Kinetic energy is inversely proportional to radius of curvature.
→
For question two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions front the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): The de-Broglie wavelength of a neutron when its kinetic energy is K is $\lambda$. Its wavelength is $2\lambda$, when its kinetic energy is 4K.
Reason (R): The de-Broglie wavelength $\lambda$ is directly proportional to square root of the kinetic energy.
→