For the Assertion (A) and Reason (R) below, choose the correct alternative.
Assertion(A) : A little gap is left between iron rails.
Reason (R) : Iron expands in summer.
Answer: A
Iron expands in summer. So, gaps are left between rails to allow for expansion.
Enter details here
Assertion (A) : Gandhiji withdrew the non-cooperation movement
Reason (R) : There was violence at the Chauri Chaura outrage
Answer: A
Gandhiji withdrew the non-cooperation movement because of the violence in the Chauri Chaura outrage.
Enter details here
Assertion (A) : Bats can fly in the night.
Reason (R) : Bats emit ultrasonics.
Answer: A
Bats can fly in the night because they can trace the obstacle in the path by perceiving the echo of the ultrasonic sound emitted by them after it is reflected by the obstacle.
Enter details here
Assertion (A) : Carbon dioxide turns lime water milky.
Reason (R) : Carbon dioxide sullies the water.
Answer: C
Carbon dioxide reacts with lime water (calcium hydroxide) to form milky precipitate of calcium carbonate
Enter details here
Assertion (A) : An atom is neutral despite the charged particles in it.
Reason (R) : The neutrons do not have any charge.
Answer: B
An atom contains the positively charged protons and an equal number of negatively charged electrons So, it is neutral
Enter details here
Assertion (A) : Leakages in household gas cylinders can be detected.
Reason (R) : LPG has a strong smell.
Answer: C
Leakages in household gas cylinders can be detected because of the strong smell of ethyl merceptan mixed with LPG.
Enter details here
Assertion (A) : Inside the earth metals are present in molten state.
Reason (R) : Earth absorbs the sun's rays.
Answer: C
Inside the earth, the high temperature and pressure keeps the metals in molten state. The earth does not absorb the sun's rays but reflects them
Enter details here
Assertion (A) : Red colour of blood is due to haemoglobin.
Reason (R) : Haemoglobin is a red pigment.
Answer: A
Haemoglobin is the blood pigment that imparts red colour to the blood.
Enter details here
Assertion (A) : Clothes are not washed properly in hard water.
Reason (A) : Hard water contains many minerals.
Answer: B
Clothes are not washed properly in hard water because it does not form lather with soap. However, it is true that hard water contains many minerals.
Enter details here
Assertion(A) : The steam engine was invented by James Watt.
Reason(R) : There was a problem of taking out water from flooded mines.
Answer: A
The problem of pumping out water from the flooded mines provided the need of self-working engine, which led James Watt to invent the same.
Thus, both A and R are true & R correctly explains A.
Enter details here