Assertion and Reason (A&R) Test
Assertion (A) : Passengers in a boat are not allowed to stand. Reason (R) : This may raise the centre of gravity of the boat .
  • A is true but R is false.
  • A is false but R is true.
  • Both A and R are false.
  • Both A and R are true and R is the correct explanation of A.
Explanation: Assertion (A) is true: Passengers in a boat are not allowed to stand because it can cause instability. Reason (R) is true: Standing raises the boat's center of gravity, making it more likely to tip over.
Assertion (A) : Telephone wires sag more in summer. Reason (R) : They expand due to summer heat.
  • A is true but R is false.
  • A is false but R is true.
  • Both A and R are false.
  • Both A and R are true but R is not the correct explanation of A.
Explanation: Assertion (A) is true: Telephone wires sag more in summer. Reason (R) is true: Metals expand when heated due to thermal expansion. R is not the complete explanation of A. While expansion due to heat causes sagging, the sagging is also influenced by the force of gravity acting on the longer, expanded wire.
Assertion (A) : Bronze is used for making statues. Reason (R) :Bronze is an alloy of copper and tin.
  • Both A and R are true but R is not the correct explanation of A.
  • Both A and R are true and R is the correct explanation of A.
  • A is true but R is false.
  • A is false but R is true.
Explanation: Assertion (A) is true: Bronze is used for making statues. Reason (R) is true: Bronze is an alloy of copper and tin. Why is R not the correct explanation? While it is true that bronze is made of copper and tin, the reason it is used for statues is due to its durability, resistance to corrosion, and ease of casting—not simply because it is an alloy. Thus, both statements are correct, but R does not fully explain why bronze is used for statues.
Assertion (A) : A person with blood group O is considered a universal recipient. Reason (R) : Type O blood does not contain any antigens.
  • A is false but R is true.
  • A is true but R is false.
  • Both A and R are false.
  • Both A and R are true but R is not the correct explanation of A
Explanation: Blood Group O: It has no antigens on red blood cells but produces anti-A and anti-B antibodies in plasma. Since it lacks A and B antigens, it can be donated to any blood group (O, A, B, AB). That’s why O-negative is called the universal donor for red blood cells. Blood Group AB: It has both A and B antigens but no antibodies in plasma. This means a person with AB blood can receive blood from any group (O, A, B, AB) without risk of an immune reaction. That’s why AB-positive is called the universal recipient for red blood cells. However, for plasma transfusions, the roles reverse—AB is the universal plasma donor, and O is the universal plasma recipient.
Assertion (A) : Pressure cookers are fitted with ebonite handles. Reason (R) : Ebonite is strong.
  • A is true but R is false.
  • A is false but R is true.
  • Both A and R are false.
  • Both A and R are true but R is not the correct explanation of A.
Explanation: Assertion (A) is true → Pressure cookers are fitted with ebonite handles. Reason (R) is true → Ebonite is strong. R is not the correct explanation of A → The main reason for using ebonite handles is that ebonite is a bad conductor of heat, preventing burns when handling the cooker.
Assertion (A) : A ship rises as it enters the sea from a river. Reason (R) : The density of sea water is higher as compared to river water.
  • Both A and R are true but R is not the correct explanation of A.
  • Both A and R are true and R is the correct explanation of A.
  • A is false but R is true.
  • A is true but R is false.
Explanation: A ship rises as it enters the sea from a river because the buoyant force acting on it increases. This happens because sea water is denser than river water due to dissolved salts. According to Archimedes' Principle, an object experiences an upward force equal to the weight of the displaced liquid. Since sea water is denser, less volume is needed to displace the same weight, causing the ship to rise.
Assertion (A) : Petrol fire cannot be extinguished by pouring water over it. Reason (R) : Water is heavier than petrol.
  • Both A and R are true and R is the correct explanation of A.
    • Explanation: Water is heavier than petrol, so it sinks while petrol floats and keeps burning. Instead of water, sand or foam should be used to put out petrol fires.