Science 2 Marks Questions

When a current is switched on through a wire, the wire starts behaving as a magnet. Hence, when a compass needle is placed near the given current carrying wire, it gets influenced by the magnetic effect of electric current and gets deflected from its North-South position.

No. The electrician cannot be allowed to replace the fuse in the house by a piece of wire. This is because every wire cannot be used as a fuse filament. A fuse filament must have a low melting point such that it could melt and break in response of large amount of current. Most of the wires have high melting points

No.

Electromagnets can only attract magnetic materials. Plastic bag is a non-magnetic material and will not be attracted by an electromagnet. Hence, an electromagnet cannot be used for separating plastic bags from a garbage heap.

No. The given circuit does not have any current source. In the absence of current, the wire does not behave as a magnet and hence, the compass needle will not show any deflection.

No, she has not taken the right step. Because due to the excessive heat of bulb, the towel may burn and it will also result in the wastage of electrical energy.

In a bulb there is a thin wire called the filament made up of tungsten. When current passes through it, it glows and gets heated up. In a heater there is a coil of wire called element which is made up of nichrome. When current passes through element it becomes red hot and give out heat.

1. BATTERY: It is a combination of two or more cells.
2. FUSE: it is a safety device in an electric circuit to prevent possible fire.
3. TORCH: it is a device portable lamp which uses battery for its operation.
4. SWITCH: it is an electric component which can make or break an electric circuit.

The strength of an electromagnet depends on the current passing through the coil and the number of coils around the core.

Following are the patterns of magnetic field lines inside and outside of a solenoid.

1. The field lines inside the solenoid are parallel straight lines.
2. The field lines outside the solenoid are curved lines.

Overloading occurs in a circuit when the current in the circuit increases abruptly. It causes overheating of the wire and might lead to the fire. It can also occur due to accidental increase in the supply voltage or on connecting too many appliances to a single socket.

1. Yes, Alpha particles being positively charged constitute a current in the direction of motion.
2. No, The neutrons being electrically neutral constitute no current.

The compass needle will not show any deflection when the switch in the circuit shown by above figure is closed, because there is no power source like cells in the circuit hence there will be no electric current flow in the circuit. In the absence of electric current there will be no magnetic effect to cause the deflection of compass needle.

No, we cannot use same fuse in a geyser and in a television set because the fuse used in every appliance has some limit to withstand the current flowing through it.
So, different appliances have fuses of different ratings.

We do cover plug pinholes which are within the reach of children with cellotape or plastic cover to avoid electric shocks. If unconsciously, a child puts his finger into the electric socket, he/she may get a shock which could be fatal.

Difference between an open circuit and a closed circuit,

Open (Electric) circuit	Closed (Electric) circuit
An open electric circuit is or electric path which begins from the positive terminal of a battery or cell, gets broken at some point.	A closed circuit is an electric path which begins from the positive terminal of a cell or battery and terminates at its negative terminal without any break.

A combination of two or more cells connected together is called a battery. It supplies electric current. It is formed by connecting the positive terminal of one cell to the negative terminal of another. To identify the positive and negative terminals, they are denoted as + and -, respectively. These batteries are used in many devices, such as torch lights, mobile phones, calculators and even automobiles.

Yes, electric current have other effect except heating, i.e. magnetic effect of current. When electric current is passed through a coil, there is a magnetic field developed around the coil or wire, if magnetic compass is placed near by, it deflects the magnetic needle.

As we know that a battery is a combination of two or more cells and it can be constructed by placing cells property on cell holder in such a way that the positive terminal of one cell is connected to the negative terminal of other. A piece of wire is connected to each of the two metal clips on the cells holder.

When an electric current flows through a wire, the wire gets heated. It is the heating effect of current or When current flows through a metal wire it gets heated up, this is called heating effect of current. E.g. a glowing electric bulb becomes warm. This effect has many applications like Electric Heater, Light Bulb etc.

The cell is the unit of battery when more than one cell are combined together, it forms a battery. In trucks, tractors and inverters, cells are internally arranged and we need not to connect it externally, so we called it as batteries.

Since, the magnetic effect directly depends on the number of turns of wire on electromagnet. So, electromagnet of Paheli will attract more pins as it has more number of turns of wire on it and thus, it is a stronger electromagnet.

The three effects of electricity are:

• Chemical effect.
• Heating effect.
• Magnetic effect.

Electromagnets can only attract magnetic materials. Plastic bag is a non - magnetic material and will not be attracted by an electromagnet. Hence, an electromagnet cannot be used for separating plastic bags from a garbage heap.

A fuse is a safety device in an electric circuit. It is made by inserting a short wire into an insulating material. Fuses are used so that if a fault occurs and too much current flows, the fuse wire melts before anything else is damaged.

The two effects of electric current are:

1. Heating effect of electric current.
2. Magnetic effect of electric current.

If we connect more of cells in the circuit, then the nail will attract more pins. It is due to the reason that the current flowing through the wire wound on the nail will get increase which in turn will increase the strength of the electromagnet.

When the current flows through any wire, a magnetic field is developed around that wire or coil and it behaves like magnet. It can be analysed by placing a magnetic compass around the wire, it will show deflection of the needle.

When electric current flows through a conductor, electrons move by spinning and orbiting nucleus. This motion of electrons produces magnetic effect. As Ampere suggested, a magnetic field is produced whenever an electrical charge is in motion.

When an electric current is passed through a coil, it gets magnetised due to phenomena of magnetic effect of current. When magnetic materials such as pins are placed near to it. It gets attracted by the coil or we can say that pins cling to the coil.

Electric fuse wire is made from some special material which has low melting point. When large electric current is passed through a circuit, it melts quickly and breaks the circuit and prevents damages to electrical circuit.

When an electric current flows through a wire, it produces magnetic effect around it. A current carrying coil of an insulated wire wrapped around a piece of iron is called an electromagnet. Magnetic Effect of electric current has many applications like Electric Bell, Motor, Fan etc.

1. Heating effect of current is used in electric heater and geyser.
2. Magnetic effect of current is used in electric bell and cranes to lift heavy magnetic materials from one place to other.

The positive terminal is represented by longer vertical line while negative terminal is represented by shorter vertical line.

Short circuits occur when the positive and negative terminals of a battery are connected by a low resistance wire, leading to the flow of large amount of current and in turn larger energy which the wire cannot carry and result in an explosion.

The two methods by which we can increase the strength of magnetic field are as follow.

1. By increasing the number of turns of wire in the coil.
2. By increasing the current flowing through the coil.