Download App

Current Electricity — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity1 Mark
Question
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: The average thermal velocity of the electrons in a conductor is zero.
Reason: Direction of motion of electrons are randomly oriented.
✓

Answer

  1. Both A and R are true, and R is the correct explanation of A.
Explanation:
ln normal conductor, the direction of electrons are randomly oriented such that the total sum of their velocities is equal to zero.

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): Nuclei having mass number about 60 are least stable.
Reason(R): When two or more light nuclei are combined into a heavier nucleus then the binding energy per nucleon will decrease.
→
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 $(A)$ : Hydrogen atom consists of only one electron but its emission spectrum has many lines
Reason $(R)$ : Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.
→
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): In a conductor, free electrons keep on moving but no magnetic force acts on a conductor in a magnetic field.
Reason (R): Force on free electron due to magnetic field always acts perpendicular to its direction of motion.
→
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): In electric circuits, wires carrying currents in opposite directions are often twisted together.
Reason (R): If the wire are not twisted together, the combination of the wires forms a current loop. 'Tile magnetic field generated by the loop might affect adjacent circuits or components.
→
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.
Assertion: Light Emitting Diode $\text{(LED)}$ emit spontaneous radiation.
Reason: $\text{LED}$ are forward-biased $p-n$ junction.
→
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): When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency as the incident frequency.
Reason (R): The frequency of monochromatic light depends on media.
→
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: An electric heater is heated first by direct and then by alternating currents. For both the currents, the potential difference across the ends of the heater is the same. The rate of production of heat will be different in two cases.
Reason: The resistance of a coil in altemating current will be more than the resistance of a coil in direct current, hence heat produced in case of direct current will be low.
→
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: The microwaves are better carriers of signals than radio wave.
Reason: The electromagnetic waves do not required any material medium for propagation.
→
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): Total energy of revolving electron in any stationary orbit is negative.
Reason (R): Energy is a scalar quantity. It can have positive or negative value.
→
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: $\frac{1}{\text{f}}=\frac{\mu_\text{g}-\mu_\text{m}}{\mu_\text{m}}\Big(\frac{1}{\text{R}_1}-\frac{1}{\text{R}_2}\Big).$
→