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: Magnesium wire bums in presence of $O_2.$
Reason: Magnesium acts as a reducing agent.
  • A
    Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
  • Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
  • C
    $A$ is true, but $R$ is false.
  • D
    $A$ is false, but $R$ is true.

Answer

Correct option: B.
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.

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

Similar questions

Assertion (A): Amoeba always produces two daughter amoebae while Plasmodium divides into many daughter cells.
Reason (R): Amoeba undergoes binary fission while Plasmodium undergoes multiple fission.

Assertion (A): Corrosion of iron is commonly known as rusting
Reason (R): Corrosion of iron occurs in presence of water and air. 

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 $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Photosynthesis takes place in green parts of the plants.
Reason : Photosynthesis always takes place in leaves.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The image of a virtual object formed by a thin converging lens is always real.
Reason : In the case of a thin lens $\frac{1}{\text{v}}-\frac{1}{\text{u}}=\frac{1}{\text{f}}$
Assertion (A): Decomposers help in recycling of nutrients between living and non-living components of ecosystem.
Reason (R): Decomposers help in decomposing dead bodies of organisms and return various nutrient elements to their source viz soil, water and air.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below:
Assertion : A solenoid tends to expand, when a current passes through it.
Reason : Two straight parallel metallic wires carrying current in same direction attract each other.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The average number of heart beat of a person at rest is about $80$ per minute.
Reason : One contraction and relaxation of the heart constitutes a complete heart beat.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below:
Assertion : The reaction of calcium with water is less violent in comparison to that of sodium.
Reason : The heat evolved is not sufficient for the hydrogen to catch fire.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : If pesticide is present in water bodies, then fish eating birds accumulate maximum amount of $\ce{DDT}$ in their bodies.
Reason : Pesticides are not metabolized within bodies of living organisms and get concentrated at each trophic level, leading to bioaccumulation.
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 $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A beam of white light gives a spectrum on passing through a hollow prism.
Reason : Speed of light outside the prism is different as the speed of light inside the prism.