Download App

Atoms — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsAtoms1 Mark
MCQ
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.
Assertion $(A):$ A tube light emits white light
Reason $(R):$ Emission of light in a tube takes place at a very high temperature.
  • 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.
  • ✓
    $A$ is false and $R$ is also false.
✓

Answer

Correct option: D.
$A$ is false and $R$ is also false.
The tube light is nothing but a gas discharge tube, which can emit light of different colours.
This colour depends mainly upon the nature of the gas inside the tube and the nature of the glass.
For neon gas the colour is bright red and for $CO_2$ it is bluish.
Again, the fluorescent glow looks yellowish green for soda glass.
So it is the nature of the glass and the gas inside the tube which determines the colour of the fluorescent glow.
As argon is filled inside a tube tight, the colour of the light is white.

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

Assertion (A): A bulb connected in series with a solenoid is connected to ac source. If a soft iron core is introduced in the solenoid, the bulb will glow brighter.
Reason (R): On introducing soft iron core in the solenoid, the inductance increases.
→
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: Radio waves cannot be diffracted by the buildings.
Reason: The wavelength of radio waves is very small.
→
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): The whole charge of a conductor cannot be transferred to another isolated conductor.
Reason (R): The total transfer of charge from one to another is not possible.
→
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 clinic lines on the magnetic map represents lines of equal dip.
Reason (R): When the horizontal and vertical components of the earth's magnetic field are equal, the angle of dip is 60º.
→
Assertion (A): The photoelectrons produced by a monochromatic light beam incident on a metal surface have a spread in their kinetic energies.
Reason (R): The energy of electrons emitted from inside the metal surface, is lost in collision with the other atoms in the metal.
→
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): There is a physical significance of matter waves.
Reason (R): Both interference and diffraction occurs in it.
→
 
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: V - I characteristic of p-n diode is same as that of any other conductor.
Reason: p-n diode behave as conductor at room temperature.
→
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: Infrared waves sometimes referred as heat waves.
Reason: Infrared waves heat up the earth surface.
→
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.
Assertion (A): If there exists coulomb attraction between two bodies, both of them may not be charged.
​​​​​​​Reason (R): ln coulomb attraction two bodies are oppositely charged.
→
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: Soft iron is used as a core of transformer.
Reason: Area of hysteresis loop for soft iron is small.
→