Electricity and Magnetism - II
Covers fundamental concepts of electricity including conductors, voltage, resistance, current flow, electric cells, and basic magnetism principles
Questions
Good conductors have many loosely bound
- atoms
- molecules
- protons
- electrons
The net e.m.f. of a normal dry cell is
- 2 volt
- 1 volt
- 1.5 volt
- 3.0 volt
The simplest way of maintaining a potential difference between the two ends of a conductor is
- to connect it to a battery or dry cell
- to bring the two ends of conductor near each other
- to mark the two ends of conductor away from each other
- none of these
In a simple voltaic cell, the negative electrode is of
- zinc
- copper
- carbon
- silver
Coating of iron with zinc is known as
- galvanization
- electroplating
- ionization
- none of these
Tungsten is mainly used for making filaments of electric bulbs because of its
- low cost
- high melting point
- high electrical conductivity
- low thermal conductivity
Ampere-second stands for the unit of
- power
- energy
- e.m.f.
- electric charge
For the movement of electrons between two points, there must be a
- temperature difference between two points
- potential difference between two points
- both points must be at the same potential
- electrons can even flow without any temperature and potential difference between two points
When a current flowing through a resistance increases four times, the heat developed will increase
- two times
- four times
- eight times
- sixteen times
Voltage can be generated
- by rubbing certain types of materials against each other
- by means of chemical reactions
- by influence of magnetism on conductors
- all of these
The property of a material, when it opposes or limits the flow of electric current through it is called
- potential difference
- electric resistance
- conductivity
- power
Fuse wire is made up of
- 63% tin and 37% lead
- 63% lead and 37% tin
- 63% tin and 37% aluminium
- 63% lead and 37% aluminium
How many 100 watt bulbs may be safely used on 220 volt with five amperes fuse?
- 22
- 11
- 10
- 5
One should not connect a number of electric appliances to the same power sockets because
- this can damage the appliances
- this can damage the domestic wiring due to over-heating
- the appliances will not get full voltage
- the appliances will not get proper current
You are given three bulbs of 25, 40 and 60 watt all operating at 220 V. Which of the three bulbs has the lowest resistance?
- 60 watt bulb
- 40 watt bulb
- 25 watt bulb
- Data insufficient
Current always flows from
- high potential to low potential
- low potential to high potential
- both of the above
- none of these
If a magnet is cut into two pieces of equal length,
- both pieces will lose their magnetism
- one piece will act as north pole and the other as south pole
- both pieces will behave as complete magnets
- one of the pieces will lose its magnetism
Find out the correct statement.
- A freely suspended bar magnet points north.
- A freely suspended bar magnet is constantly oscillating.
- A freely suspended bar magnet always points east.
- A freely suspended bar magnet will set itself at an angle to the horizontal.
When a bar magnet is immersed in a heap of iron fillings and is then taken out, it is observed that iron fillings stick to the surface of the bar magnet. The iron fillings would be observed to
- stick uniformly throughout the surface of the bar magnet
- stick randomly on the surface of bar magnet
- have maximum concentration at the two ends of the bar magnet
- have maximum concentration slightly away from the two ends of the bar magnet