Define the terms: current, potential difference, resistance, resistivity, power 2 Define (i)the unit of current, (ii) the unit of potential difference(iii) the unit of resistance (iv) the unit of power (v) commercial unit of power 3 State Ohms law and write an activity to verify the same. Does it hold good in all conditions? 4 State joules law of heating .
Answers
Answer:
Potential Difference: The difference between the potential of positive and negative ions of current is called P.D
Resistance: The stooping power of the medium through which Current flow is called Resistance
Resistivity:The electrical resistivity is the electrical resistance per unit length and per unit of cross-sectional area at a specified temperature. The SI unit of electrical resistivity is the ohm⋅metre (Ω⋅m). It is commonly represented by the Greek letter ρ, rho
Electric power: Rate at which electrical energy is consumed in an electrical circuit. The SI unit of power is the watt, which is one joule per second.
(i)the unit of current ⇒ Ampere(A)
(ii) the unit of potential difference ⇒ Volt(V)
(iii) the unit of resistance ⇒ ohm (Ω)
(iv) the unit of power ⇒ watt(W)
(v) commercial unit of power ⇒ Kilowatt - hour(unit)
Ohm's law show the relationship between potential difference and current, where as it states that potential difference is directly propotional to current
mathematical expression for ohm's law is
V α I
i.e., V=IR
Factors affecting resistence
- length [R ∝ l]
- area of cross section [R ∝ 1/A]
- nature of material
- temparature [R ∝ T]
Joule's law of heating states that when a current 'i ' passes through a conductor of resistance 'r' for time 't' then the heat developed in the conductor is equal to the product of the square of the current, the resistance and time.
HOPE THIS HELPS YOU............
PLZ MARK AS BRAINLEST...............
Answer:
Current : Current is the flow of charge. We measure current by counting the amount of charge passing through a boundary in one second.
potential difference: the difference of electrical potential between two points.
power :Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit.
Q2
(i) unit of current :The SI unit of electric current is the ampere, which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit Electric current is measured using a device called an ammeter.
(ii) the unit of potential difference : The S.I unit of potential difference is volt. One volt is equal to the energy consumed by one joule per electric charge. Volt is the "derived unit" for electric potential
(iii) the unit of resistance :The ohm (symbol: Ω) is the SI derived unit of electrical resistance.
(iv) the unit of power : In terms of current and voltage it is P=IV. The energy used is the amount of charge q moved through voltage V in a time interval t.
(v) commercial unit of power : The commercial unit of electrical energy is kilo watt hour (kWh).
Q3
Ohm's law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change.
ACTIVITY
Material required :
batteries of 1.5 V, Conducting wires, iron spoke, LED bulb, ammeter, volt meter,
Procedure:
• Arrange the circuit as shown in the attachment.
• Connect the battery..and note the values of I and V in a table.
• Connect 2, 3, 4 and 5 batteries and note the values of I and V in each case.
• Observe the temp. of spoke
• Next find the value of V/I in each case
• Now, remove the Iron spoke and connect the LED.
• Do the same..by connecting battries and note the values
• observe the temp. of LED
• Next find the value of V/I in each case.
• Draw the graphs..for the both iron spoke and LED cases and observe
Observation :
It will observed that the, V/I value is constant for IRON SPOKE..but, it isn't for LED
Also, the Temp. of Spoke is constant. But, the temp. of LED is not constant!
The graph of the values of I and V of spoke is linear..but, it is not linear for LED.
Result :
The constant value of V/I..indicates that,the potential diff.is directly proportional to Current
Q4 Joule's law of heating states that when a current 'i ' passes through a conductor of resistance 'r' for time 't' then the heat developed in the conductor is equal to the product of the square of the current, the resistance and time.
HOPE IT HELPS U :3