Advertisements
Advertisements
प्रश्न
1 calorie = _________ joule.
Advertisements
उत्तर
1 calorie = 4.18 joule
APPEARS IN
संबंधित प्रश्न
Name two safety devices which are connected to the live wire of a household electric circuit
What is the maximum power in kilowatts of the appliance that can be connected safely to a 13 A ; 230 V mains socket?
An electric fan runs from the 230 V mains. The current flowing through it is 0.4 A. At what rate is electrical energy transferred by the fan?
The SI unit of energy is :
(a) joule
(b) coulomb
(c) watt
(d) ohm-metre
1kWh = …….. J
A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V.
calculate:
(i) the resistance of the wire and
(ii) the heat energy produced in 1 minute.
Water in an electric kettle connected to a 220 V supply took 5 minutes to reach its boiling point. How long would it have taken if the supply voltage had fallen to 200 V?
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.

(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
A potential difference of 6 V is applied across a 3 Ω resistor. What is the current flowinq throuqh the circuit?
Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance.
What does the unit kilowatt hour measure? Define it.
Name a metal that is used as an electron emitter. Give one reason for using this metal.
Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the resistance of each heater.
I ampere of current is passed through a resistor of resistance R ohm for time t second. Obtain expression for
(i) the electrical energy, and
(ii) the electrical power spent.
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate:
(i) the current drawn,
(ii) the electrical energy consumed in 60 hours,
(iii) the cost of electrical energy consumed at Rs. 2.50 per kWh.
The unit of e.m.f. of a cell is ____________.
1 kWh = ______ J.
Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is ______
