Advertisements
Advertisements
Question
The heat produced in a wire of resistance 'x' when a current 'y' flows through it in time 'z' is given by:
(a) x2 × y × z
(b) x × z × y2
(c) y × z2 × x
(d) y × z × x
Solution
`x xx zxx y^2`
This is so because heat, H = I2Rt
APPEARS IN
RELATED QUESTIONS
Two exactly similar heating resistances are connected (i) in series, and (ii) in parallel, in two different circuits, one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.
Give a scientific reason.
For electric power transmission, copper or aluminium wire is used.
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?
How does use of a fuse wire protect electrical appliances?
Can we use the same fuse in a geyser and a television set? Explain.
Your teacher has shown you the following activity.
Activity: The teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. The free ends of the wire are connected to a cell through a switch as shown in Figure 14.3. The current is switched on and some pins are placed near the ends of the nail.
Write down any three questions that come to your mind about this activity
Explain the working of an electric fuse.
What is a trip switch?
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
