Download App

Current Electricity — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity1 Mark
MCQ
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: Two bulbs of same wattage, one having a carbon filament and the other having a metallic filament are connected in series. Metallic bulbs will glow more brightly than carbon filament bulb.
Reason: Carbon is a semiconductor.
  • 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.
When two bulbs are connected in series, the resistance of the circuit increases and so the voltage in each decreases, hence the brightness and the temperature also decreases. Due to decrease in temperature, the resistance of the carbon filament will slightly increase while that of metal filament will decrease. Hence, carbon filament bulb will glow more brightly $(P = i^2R).$ Also, carbon is not a semiconductor.

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 Current Electricity→Current Electricity — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

Assertion (A): In photoemissive cell inert gas is used.
Reason (R): inert gas in the photoemissive cell gives greater current.
→
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 earth's magnetic field is due to iron present in its core.
Reason (R): At a low temperature magnet losses its magnetic property or magnetism.
→
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.
→
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.
→
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: Basic difference between an electric lines of force and magnetic lines of force is that former is discontinuous and the latter is continuous or endless.
Reason: No electric lines of force exist inside a charged body but magnetic lines do exist inside a magnet.
  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 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.
→
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: At absolute zero the conductivity of semiconductor is zero.
Reason: In a semiconductor there are no free electrons at any 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: X-rays in vacuum travel faster than light waves in vacuum
Reason: The energy of X-rays photon is less than that of light photon.
→
Assertion (A): To observe diffraction of light, the size of the obstacle/aperture should be of the order of $10^{-7} m$.
Reason (R): $10^{-7}$ is the order of the wavelength of visible light.
→
For question, 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): Energy is released in a nuclear reaction.
Reason (R): In any nuclear reaction the reactants and resultant products obey the law of conservation of charge and mass only.
→