Electricity â Resistance & Heating Effect (āĻŦāĻŋāĻĻā§āĻ¯ā§ā§ â ā§°ā§āĻ§ āĻā§°ā§ āĻ¤āĻžāĻĒā§āĻ¯āĻŧ āĻĒā§ā§°āĻāĻžā§ą)
Q. Total resistance of resistors in parallel is - āĻĒā§ā§°āĻļā§āĻ¨: āĻ¸āĻŽāĻžāĻ¨ā§āĻ¤ā§°āĻžāĻ˛ āĻ¸āĻāĻ¯ā§āĻāĻ¤ āĻŽā§āĻ ā§°ā§āĻ§ āĻā§āĻ¨ā§āĻā§ā§ąāĻž āĻšāĻ¯āĻŧ ?
Ans: Less than each individual resistance āĻāĻ¤ā§āĻ¤ā§°: āĻĒā§ā§°āĻ¤āĻŋāĻā§ āĻĒā§āĻĨāĻ ā§°ā§āĻ§āĻ¤āĻā§ āĻāĻŽ
Explanation: Parallel connection provides multiple current paths. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ¸āĻŽāĻžāĻ¨ā§āĻ¤ā§°āĻžāĻ˛ āĻ¸āĻāĻ¯ā§āĻāĻ¤ āĻĒā§ā§°āĻŦāĻžāĻšā§° āĻŦāĻšā§ āĻĒāĻĨ āĻĨāĻžāĻā§, āĻ¸ā§āĻ¯āĻŧā§āĻšā§ āĻŽā§āĻ ā§°ā§āĻ§ āĻāĻŽ āĻšāĻ¯āĻŧāĨ¤
Q. Two 1 Ω resistors connected in parallel: equivalent resistance = ?
āĻĒā§ā§°āĻļā§āĻ¨: āĻĻā§āĻāĻž ā§§ Ω ā§°ā§āĻ§ āĻ¸āĻŽāĻžāĻ¨ā§āĻ¤ā§°āĻžāĻ˛ āĻ¸āĻāĻ¯ā§āĻ āĻā§°āĻŋāĻ˛ā§ āĻ¸āĻŽāĻ¤ā§āĻ˛ā§āĻ¯ ā§°ā§āĻ§ āĻāĻŋāĻŽāĻžāĻ¨ ?
Ans: 0.5 Ω āĻāĻ¤ā§āĻ¤ā§°: ā§Ļ.ā§Ģ Ω
Explanation: For two equal resistors in parallel: Req = R/2â So, R = 1Ω, therefore Req = 0.5Ω
āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ¸āĻŽāĻžāĻ¨ āĻĻā§āĻāĻž ā§°ā§āĻ§ āĻ¸āĻŽāĻžāĻ¨ā§āĻ¤ā§°āĻžāĻ˛ āĻ¸āĻāĻ¯ā§āĻ āĻā§°āĻŋāĻ˛ā§ āĻ¸āĻŽāĻ¤ā§āĻ˛ā§āĻ¯ ā§°ā§āĻ§ āĻ ā§°ā§āĻ§ā§āĻ āĻšāĻ¯āĻŧāĨ¤
Q. Two/three resistances in series example (sum = 302 Ω) āĻĒā§ā§°āĻļā§āĻ¨: āĻ§āĻžā§°āĻžāĻŦāĻžāĻšāĻŋāĻ āĻ¸āĻāĻ¯ā§āĻāĻ¤ ā§°ā§āĻ§āĻ¸āĻŽā§āĻšā§° āĻ¯ā§āĻāĻĢāĻ˛ ā§Šā§Ļā§¨ Ω āĻā§āĻ¨ā§āĻā§ āĻšāĻ¯āĻŧ ?
Ans: 302 Ω āĻāĻ¤ā§āĻ¤ā§°: ā§Šā§Ļā§¨ Ω
Explanation: In a series connection, total resistance is the sum of all resistances. R = R1 + R2 + R3
Example: 10Ω + 12Ω + 280Ω = 302Ω
In series connection, resistances add directly. 10 + 12 + 280 = 302Ω
Ans: Less than its emf āĻāĻ¤ā§āĻ¤ā§°: emf āĻ¤āĻā§ āĻāĻŽ
Explanation: Internal resistance causes voltage drop. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ āĻā§āĻ¯āĻ¨ā§āĻ¤ā§°ā§āĻŖ ā§°ā§āĻ§ā§° āĻŦāĻžāĻŦā§ āĻŦāĻŋāĻā§ą āĻĒāĻžā§°ā§āĻĨāĻā§āĻ¯ āĻāĻŽāĻŋ āĻ¯āĻžāĻ¯āĻŧāĨ¤
Q. Value of 1 joule in calories ? āĻĒā§ā§°āĻļā§āĻ¨: ā§§ āĻā§āĻ˛ āĻāĻŋāĻŽāĻžāĻ¨ āĻā§āĻ˛ā§°āĻŋā§° āĻ¸āĻŽāĻžāĻ¨ ?
Ans: ≈ 0.24 calorie āĻāĻ¤ā§āĻ¤ā§°: āĻĒā§ā§°āĻžāĻ¯āĻŧ ā§Ļ.ā§¨ā§Ē āĻā§āĻ˛ā§°āĻŋ
Explanation: 1 cal ≈ 4.2J, āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: ā§§ āĻā§āĻ˛ āĻĒā§ā§°āĻžāĻ¯āĻŧ ā§Ļ.ā§¨ā§Ē āĻā§āĻ˛ā§°āĻŋā§° āĻ¸āĻŽāĻžāĻ¨āĨ¤
Q. When current is drawn from a cell, terminal potential difference is - āĻĒā§ā§°āĻļā§āĻ¨: āĻā§āĻˇā§° āĻĒā§°āĻž āĻĒā§ā§°āĻŦāĻžāĻš āĻ˛’āĻ˛ā§ āĻāĻžā§°ā§āĻŽāĻŋāĻ¨ā§āĻ˛ āĻŦāĻŋāĻā§ą āĻĒāĻžā§°ā§āĻĨāĻā§āĻ¯ āĻā§āĻ¨ā§āĻā§ā§ąāĻž āĻšāĻ¯āĻŧ ?
Ans: Less than its emf āĻāĻ¤ā§āĻ¤ā§°: emf āĻ¤āĻā§ āĻāĻŽ
Explanation: When current flows through a cell, internal resistance causes some voltage loss. Therefore terminal potential difference becomes less than emf. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻā§āĻˇā§° āĻŽāĻžāĻā§ā§°ā§ āĻĒā§ā§°āĻŦāĻžāĻš āĻ’āĻ˛ā§ āĻ āĻā§āĻ¯āĻ¨ā§āĻ¤ā§°ā§āĻŖ ā§°ā§āĻ§ā§° āĻŦāĻžāĻŦā§ āĻāĻŋāĻā§ āĻŦāĻŋāĻā§ą āĻšā§ā§°āĻžāĻ¸ āĻĒāĻžāĻ¯āĻŧāĨ¤ āĻ¸ā§āĻ¯āĻŧā§ āĻāĻžā§°ā§āĻŽāĻŋāĻ¨ā§āĻ˛ āĻŦāĻŋāĻā§ą āĻĒāĻžā§°ā§āĻĨāĻā§āĻ¯ emf āĻ¤āĻā§ āĻāĻŽ āĻšāĻ¯āĻŧāĨ¤
Q. SI unit of energy ? āĻĒā§ā§°āĻļā§āĻ¨: āĻļāĻā§āĻ¤āĻŋā§° SI āĻāĻāĻ āĻāĻŋ ?
Ans: Joule (J) āĻāĻ¤ā§āĻ¤ā§°: āĻā§āĻ˛ (J)
Explanation: Joule is the SI unit of energy and work. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻā§āĻ˛ āĻšā§āĻā§ āĻļāĻā§āĻ¤āĻŋ āĻā§°ā§ āĻāĻžāĻŽā§° SI āĻāĻāĻāĨ¤
Q. Which effect of electric current does an electric heater use ? āĻĒā§ā§°āĻļā§āĻ¨: āĻŦā§āĻĻā§āĻ¯ā§āĻ¤āĻŋāĻ āĻšāĻŋāĻāĻžā§°ā§ āĻŦāĻŋāĻĻā§āĻ¯ā§āĻ¤ā§° āĻā§āĻ¨ āĻĒā§ā§°āĻāĻžā§ą āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°ā§ ?
Ans: Thermal (heating) effect āĻāĻ¤ā§āĻ¤ā§°: āĻ¤āĻžāĻĒā§āĻ¯āĻŧ āĻĒā§ā§°āĻāĻžā§ą
Explanation: Current passing through resistance produces heat. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: ā§°ā§āĻ§ā§° āĻŽāĻžāĻā§ā§°ā§ āĻĒā§ā§°āĻŦāĻžāĻš āĻ’āĻ˛ā§ āĻ¤āĻžāĻĒ āĻā§āĻĒāĻ¨ā§āĻ¨ āĻšāĻ¯āĻŧāĨ¤
Q. Material used for electric heater coils ? āĻĒā§ā§°āĻļā§āĻ¨: āĻŦā§āĻĻā§āĻ¯ā§āĻ¤āĻŋāĻ āĻšāĻŋāĻāĻžā§°ā§° āĻāĻ¯āĻŧā§āĻ˛āĻ¤ āĻā§āĻ¨ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°āĻž āĻšāĻ¯āĻŧ ?
Ans: Nichrome āĻāĻ¤ā§āĻ¤ā§°: āĻ¨āĻžāĻāĻā§āĻ°ā§āĻŽ
Explanation: Nichrome has high resistance and heat tolerance. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ¨āĻžāĻāĻā§āĻ°ā§āĻŽā§° ā§°ā§āĻ§ āĻŦā§āĻāĻŋ āĻā§°ā§ āĻ āĻāĻā§āĻ āĻ¤āĻžāĻĒ āĻ¸āĻšā§āĻ¯ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°ā§āĨ¤
Q. The property of a circuit that converts electrical energy into heat is - āĻĒā§ā§°āĻļā§āĻ¨: āĻŦāĻ°ā§āĻ¤āĻ¨ā§āĻ¤ āĻŦāĻŋāĻĻā§āĻ¯ā§ā§ āĻļāĻā§āĻ¤āĻŋāĻ āĻ¤āĻžāĻĒāĻ¤ āĻĒā§°āĻŋāĻŖāĻ¤ āĻā§°āĻž āĻā§āĻŖāĻā§ āĻāĻŋ ?
Ans: Resistance āĻāĻ¤ā§āĻ¤ā§°: ā§°ā§āĻ§
Explanation: Resistance causes Joule heating in circuits. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: ā§°ā§āĻ§ā§° āĻŦāĻžāĻŦā§ āĻŦāĻ°ā§āĻ¤āĻ¨ā§āĻ¤ āĻ¤āĻžāĻĒ āĻā§āĻĒāĻ¨ā§āĻ¨ āĻšāĻ¯āĻŧāĨ¤