Thermal effect of electric current - class-XII
Description: thermal effect of electric current | |
Number of Questions: 88 | |
Created by: Girish Devgan | |
Tags: current electricity electric current through conductors effects of electric current electricity electric current and circuit electric current physics electrical appliances in everyday life electricity and magnetism electric charge and electric current effect of electric current effects of current electric current and its effects |
In any electric circuit, when the switch is on and the current is flowing through it why do the wire, switches, bulb or devices in the circuit become hot?
A metal plate can be heated by
When electric current is flown through a conductor, some amount of:
The temperature of a metal wire rises when an electric current is passed through it because:
When a current flows through a conductor, its temperature
A lamp is marked 60 W, 220 V. If it operates at 200 V, the rate of consumption of energy will _____
The amount of heat produced in a wire depends on its material-
Heat produced in a resistor when current is passed through it depends upon-
One megawatt is equivalent to
What will be the current drawn by an electric fan of 805 W, when it is connected to a source of 230 V ?
Electrical work done per unit time is
When a current flows through a conductor its temperature
Heating effect of current is due to
Whenever an electric current is passed through a conductor,it gets heated up.this means that a part of electrical energy, given to the conductor, gets converted to
An electric bulb generally uses a filament coated with
Which of the following is/are energy efficient products?
Why CFL is better in comparison to bulb ?
Shivam went for buying a CFL from D-mart, what safety mark he should look for?
Which of the following will produce maximum wastage of electricity ?
Several electric bulbs designed to be used on a 220 V electric supply are rated 20 W each. How many lamps can be connected in parallel with each other across the two wires of 220 V line, if the maximum allowable current is 5 A?
An electric heater kept in vacuum is heated continuously by passing electric current. Its temperature:
Choose the incorrect option: Expansion during heating:
A coil and a bulb are connected in series with a $12$ volt direct current source. A soft iron core is now inserted in the coil. Then
Appliances based on heating effect of current work on
Fill in the blank.
An appliance / machine which does not use an electric motor is
A copper voltameter is connected in series with a coil of resistance $10 \Omega $. When a steady current is passed through the circuit, $0.297 g$ of copper is found to be deposited at the cathode in $15 min$. The electrochemical equivalent of copper is $3.3 \times 10^{-7} kg C^{-}$. Heat liberated in the coil is:
Rate of dissipation of Joules heat in resistance per unit volume is (symbols have usual meaning)
The essential requirements for a good heating element are _________________.
If the current is flowing through a $10 \Omega$ resistor, then in which case the maximum heat will be generated?
What is CFL ?
Name the effect of current responsible for the glow of the bulb in an electric circuit.
A house is fitted with 10 tubes of 40 W. If all tubes are lighted for 10 hours and if the cost of one unit of electricity energy is Rs. 2.50 the total cost of electricity consumption is ...
The resistance of a hot tungsten filament is about $10$ times the cold resistance. What will be the resistance of $100\ W,\ $$200\ V$ lamp when not in use?
Calculate the energy consumed by $2\ kW$ heater used for $1\ hr$ every day in a period of $30\ \text{days}$.
You have the following appliances each of $500\ W$ running on $220\ V$ a.c.:
An electric lamp is marked $60\ W,\ 220\ V$. The cost of kilo watt hour of electricity is $Rs.\ 1.25$. The cost of using thing lamp on $220\ V$ for $8\ hrs$ is:
An electric bulb of $60\ W$ is used for $6\ hrs/day$. Calculate the units of energy consumed in one day by the bulb.
An electric bulb of $30\ W$ consumes $0.72$ units of energy in a day. Find the number of hours it is working in a day?
For a heater rated at 4.4 kW; 220 V . Calculate the energy consumed by the heater in 4 hours?
How much units of energy is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days)
Which of the following is true for electrical energy?
When we pay for our electricity bill, we are paying for the:
An electric kettle is rated as $2.5\ kW, \ 250\ V$. Find the cost running the kettle for two hours at $60\ \text{paisa}/\text{unit}$.
An electric bulb rated for $500$W at $100$ V is used in a circuit having a $200$V supply. The resistance R that one must put in series with the bulb, so that the power delivered in the bulb is $500$W is ______$\Omega$.
Four bulbs, each of rating (100 W, 220 V) and connected in parallel across a voltage supply of 220 V, are operated for five hours daily. If all the bulbs are replaced by LEDs of rating (8 W, 220 V), how many units of electrical energy will be saved every month (30 days)?
How much energy in kilowatt hour is consumed in operating ten 50 watt bulbs for 10 hours per day in a month (30 days)
If voltage across a bulb rated $220V-100W$ drops by $2.5$% of its rated value, the percentage of the rated value by which the power would decrease is
A padcular ohmmeter uses a battery to provide a potential difference across an unknown resistance whose value S to be measured. The meter measures the resulting current through this resistor and is calibrated to read out corresponding value of resistance. Suppose that this ohmmeter is used to measure he resistance of a typical incandescent tungsten-filament light bulb. The value of the resistance of the light bulb will be
A $500\ W$ heating unit is designed to operate on a $115\ V$ line. If line voltage drops to $110\ V$ line, the percentage drop in heat output will be:
An electric heater operating at $220\ V$ boils $5\ l$ of water in $5\ \text{minutes}$. If it is used on a $110\ V$ line, it will boil the same amount of water in:
The maximum current $I$, which can be passed through a fuse without melting varies with its radius $r$ as:
If current is flowing through a 10 $\Omega$ resistor, then indicate in which case the maximum heat will be generated?
The energy expended in $1\ kW$ electric heater in $30\ \text{seconds}$ will be:
A resistor has resistance R. When the potential difference across the resistor is V, the current in
the resistor is I. The power dissipated in the resistor is P. Work W is done when charge Q flows
through the resistor.
What is not a valid relationship between these variables?
Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. The energy supplied in kWh to the three heaters in 5 hours is :
A geyser is rated 1500 W, 250 V. This geyser is connected to 250 V mains. The cost of energy consumed at Rs. 4.20 per kWh for 5 hours will be :
A lamp of $100\ W$ and a heater of $1\ kW$ are in simultaneous use for $10\ hrs$. The units of electricity consumed according to the meter in the house is:
A motor of $50\ W$ runs for $20\ hrs$. How many 'units' ($kWh$) of electrical energy are consumed?
A heater is marked 1000 W. The energy consumed by it in ten hours is
Which of these will consume most units of energy in a day?
A current of $4 A$ flows through a $12 V$ car headlight bulb for $10$ minutes, how much energy is consumed?
Calculate the monthly bill if a heater of 100 watt is used at the rate of rs. 1 per unit for 1 hour daily.
What should be the bill for the month of March for a heater of resistance $\displaystyle $ connector to 220V mains. The cost of energy is Rs.1 kWh and the heater is used 1 hour daily.
Calculate the total power of 2 fans, if each of them draws a current of $5 A$ at a p.d of $200 V$.
A current of $0.5 A$ flows through a resistance of $10 \Omega$ for $\dfrac{1}{2}$ hour. Find the amount of electrical energy consumed by resistance.
Calculate the energy transferred by a $5 A$ current flowing through a resistor of $20 \ ohms$ for $30$ minutes.
An electric bulb is rated $750 \omega - 200 V$. Calculate the magnitude of current.
An electric bulb of resistance $480 \Omega$ is connected to $220 V$. Find electric energy consumed in $10 s$.
A bulb of $2.5 V$, draws a current of $0.5 A$. If the bulb is switched on for 2 minutes, calculate the energy released by the bulb.
A light bulb has the resistance of tungsten resistance which convert about 10% electrical energy into visible light. If energy other than visible is waste energy. How many kilo-joules does a light bulb wasted in one hour?
An electric kettle is rated as 2.5 kW, 250 V, Find the cost of running the kettle for two hours at 60 paisa per unit.
A table lamp of power 60 W consumed 9 (commerical) units of electricity in the month of April. For how many hours per day, on an average, was the lamp in use?
A $100W, 200V$ bulb is connected to a $160V$ supply. The actual power consumption would be
$4$ bulbs rated $100$W each, operate for $6$ hours per day. What is the cost of the energy consumed in $30$ days at the rate of Rs. $5$/kWh?
Why is the switch for any electrical appliance always fitted on to the live wire ?
In an electrical circuit three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?
A table lamp of power 60 W consumed 9 (commercial) units of electricity in the month of April. For how many hours per day, on an average, was the lamp in use?
An air conditioner is rated $240\ V, 1.5\ kW$. The air conditioner is switched on $8\ hrs$ each day. What is electrical energy consumed in $30\ days$?
Two electric bulbs rated ${P} _{1}$ and watt at $V$ volt are connected in series across $V$ volt mains, then their total power consumption $P$ is
An electric bulb is connected to a $20$ V battery of negligible internal resistance. The resistance offered by the bulb is $5$ $\Omega$. The electrical energy consumed by the bulb in $3$ hours is _____ kWh.
What should be the bill for the month of April for a heater of resistance 60.5 $\Omega$ connected 220 V mains, The cost of energy is Rs 2 per kWh and the heater is used for 3 hours daily?
Laws of heating is given by :
An electric fan is switched on in a closed room. The air in the room is
Law of heating was given by
According to Joule's Law, Which of the quantities do not affect heat produced in a resistor?
A/C to Joule's law