Physics
Assertion (A) : A bucket filled with water is heavier till it is immersed in water in well.
Reason (R) : The effect of upthrust is that the weight of body immersed in liquid appears to be lighter than its actual weight.
- both A and R are true and R is the correct explanation of A
- both A and R are true and R is not the correct explanation of A
- assertion is false but reason is true
- assertion is true but reason is false
Answer
assertion is false but reason is true
Explanation
Assertion (A) is false because when a bucket is lowered into a well, as it gets immersed in the water, it experiences an upward buoyant force (upthrust) which reduces its apparent weight, so the bucket feels lighter till it is immersed in water in well and once it is taken outside the water it gets heavier due to absence of upthrust.
Reason (R) is true because this is the definition of buoyancy which states that the upthrust reduces the apparent weight of the object in the fluid.
Related Questions
A student is given three liquids A, B and C of densities ρ1, ρ2 and ρ3. He has to arrange these liquids in order of their increasing densities. To do so, he takes an object and dips it in each liquid and observes that the object floats with 1/9, 2/11 and 3/7 parts of its volume outside the surface of liquid A, B and C respectively. The correct order is :
- ρ1 > ρ2 > ρ3
- ρ2 > ρ3 > ρ1
- ρ3 > ρ2 > ρ1
- ρ3 > ρ1 > ρ2
Assertion (A) : A body when weighed by a spring balance, weighs slightly less in air than in vacuum.
Reason (R) : This is so because of upthrust of air on body.
- both A and R are true and R is the correct explanation of A
- both A and R are true and R is not the correct explanation of A
- assertion is false but reason is true
- assertion is true but reason is false
Assertion (A) : An iron nail sinks in water, but floats in mercury.
Reason (R) : The density of iron is equal to density of mercury but greater than water.
- both A and R are true and R is the correct explanation of A
- both A and R are true and R is not the correct explanation of A
- assertion is false but reason is true
- assertion is true but reason is false
Assertion (A) : A loaded ship is submerged more while an unloaded ship is less submerged.
Reason (R) : A loaded ship displaces more water in comparison to an unloaded ship in order to float.
- both A and R are true and R is the correct explanation of A
- both A and R are true and R is not the correct explanation of A
- assertion is false but reason is true
- assertion is true but reason is false