Two wires X and Y are of equal length and have equal resistances. If the resistivity of X is more than
that of Y, which wire is thicker and why ? For the electric circuit given below calculate :
30 11
(i) Current in each resistor
(ii) Total current drawn from the battery and
(iii) Equivalent resistance of circuit
(a) While diluting an add, why is it recommended that the add should be added to water and not water to the acid ?
(b) Explain why aqueous solution of an add conducts electricity.
(c) You have four solutions A, B, C and D. The pH of solution A is 6,B is 9, C is 12 and D is 7.
(i) Identify the most acidic and the moat basic of the solutions.
(ii) Arrange the above four solutions in the increasing order of their lir ion concentration.
(iii) State the change in colour of pH paper on dipping in solution C and D.
CBSE Class X Science LA (5 Marks)
Answers
Answer:
Explanation:
Two wires X and Y are of equal length and have equal resistances.
X - R₁ & Y - R₂
R₁ = ρ₁ L₁ /A₁
R₂ = ρ₂ L₂ /A₂
R₁ = R₂
L₁ = L₂ = L
=> ρ₁ L /A₁ = ρ₂ L /A₂
=> ρ₁ /A₁ = ρ₂ /A₂
=>ρ₁/ρ₂ = A₁ /A₂
ρ₁ > ρ₂
=> A₁ > A₂
Wire X is thicker
While Diluting an acid , if we add water in acid then it will make very much concentrated acidic solution which may boil and cause harm to the person performing actions.
Thats why acid is added in water
You have four solutions A, B, C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7.
The pH scale ranges from 0 to 14.
pH of 7 is neutral. A
pH less than 7 is acidic. A
pH greater than 7 is basic.
A is most acidic
C is most basic
Wire X is more thicker than Wire Y.
Explanation:
Expression for resistance is,
R = ρ× where,
ρ = Resistivity of the wire
l = Length of the wire
A = Area of cross section of wire
Since, Resistance and length of X and Y is same and
Resistivity of X is greater than Resistivity of Y.
Area of X should be greater than Y.
∴ Wire X is thicker than wire Y.