(a) Corrosion - Metals react with oxygen which is present in the atmospheric moisture. This leads to the formation of metal oxides. In due course of time, the metal keeps on changing into its oxide and finally the whole metal is lost due to oxidation. This process is called corrosion. Example: IronRead more
(a) Corrosion – Metals react with oxygen which is present in the atmospheric moisture. This leads to the formation of metal oxides. In due course of time, the metal keeps on changing into its oxide and finally the whole metal is lost due to oxidation. This process is called corrosion.
Example: Iron articles; like iron gates or bridges tend to rust because of oxidation by atmospheric moisture. We know that rust is nothing but iron oxide. Conversion of iron into rust leads to corrosion of the iron articles. Due to this, the iron articles weaken and finally wither away.
(b) Rancidity – When fats and oils are oxidised, their smell and taste change. This process is called rancidity. Oily food often become rancid and start giving out obnoxious smell. The taste also becomes bad. Such oily food is not fit for eating.
Example: When packets of potato chips or other oily snacks are kept open for a long time; their taste and smell become bad. The oily food is no longer safe to eat.
Compass needle is a bar magnet when it is brought near a bar magnet, its magnetic field interacts with the magnetic field line of the bar magnet. Therefore deflection occurs in the compass needle.
Compass needle is a bar magnet when it is brought near a bar magnet, its magnetic field interacts with the magnetic field line of the bar magnet. Therefore deflection occurs in the compass needle.
The properties of magnetic field lines are: (a) Magnetic field lines emerge from the north pole. (b) They merge at the south pole. (c) The direction of field lines inside the magnet is from the south pole to the north pole. (d) Magnetic lines do not intersect with each other.
The properties of magnetic field lines are:
(a) Magnetic field lines emerge from the north pole.
(b) They merge at the south pole.
(c) The direction of field lines inside the magnet is from the south pole to the north pole.
(d) Magnetic lines do not intersect with each other.
Two magnetic lines never intersect because if two field lines of a magnet intersect, then at the point of intersection, the compass needle points in two different directions which is not possible at same time a needle shows to different directions. Hence, they never interact.
Two magnetic lines never intersect because if two field lines of a magnet intersect, then at the point of intersection, the compass needle points in two different directions which is not possible at same time a needle shows to different directions. Hence, they never interact.
Inside the loop = Pierce inside the table Outside the loop = Appear to emerge out from the table For the downward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside tRead more
Inside the loop = Pierce inside the table
Outside the loop = Appear to emerge out from the table
For the downward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop. Similarly, for the upward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop.
(c) and (d) When a proton enters an area of magnetic field, it experiences a magnetic force. As a result of the force, the path of the proton becomes circular. Therefore, its velocity and momentum change.
(c) and (d)
When a proton enters an area of magnetic field, it experiences a magnetic force. As a result of the force, the path of the proton becomes circular. Therefore, its velocity and momentum change.
(d) The direction of the magnetic field can be determined by applying Fleming’s left hand rule. According this rule, if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the cRead more
(d) The direction of the magnetic field can be determined by applying Fleming’s left hand rule. According this rule, if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the direction of magnetic field. As the direction of a positively charged alpha particle is towards west, the direction of current will be the same i.e., towards the west. If the direction of magnetic force is towards the north. Hence, according to Fleming’s left hand rule, the direction of the magnetic field will be upwards.
Fleming’s left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the diRead more
Fleming’s left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the direction of magnetic field.
The principle of an electric motor is based on the magnetic effect of current. A current-carrying loop experiences a force and rotates when placed in a magnetic field. The direction of rotation of the loop is determined by Fleming's left-hand rule.
The principle of an electric motor is based on the magnetic effect of current. A current-carrying loop experiences a force and rotates when placed in a magnetic field. The direction of rotation of the loop is determined by Fleming’s left-hand rule.
Explain the following terms with one example each.
(a) Corrosion - Metals react with oxygen which is present in the atmospheric moisture. This leads to the formation of metal oxides. In due course of time, the metal keeps on changing into its oxide and finally the whole metal is lost due to oxidation. This process is called corrosion. Example: IronRead more
(a) Corrosion – Metals react with oxygen which is present in the atmospheric moisture. This leads to the formation of metal oxides. In due course of time, the metal keeps on changing into its oxide and finally the whole metal is lost due to oxidation. This process is called corrosion.
See lessExample: Iron articles; like iron gates or bridges tend to rust because of oxidation by atmospheric moisture. We know that rust is nothing but iron oxide. Conversion of iron into rust leads to corrosion of the iron articles. Due to this, the iron articles weaken and finally wither away.
(b) Rancidity – When fats and oils are oxidised, their smell and taste change. This process is called rancidity. Oily food often become rancid and start giving out obnoxious smell. The taste also becomes bad. Such oily food is not fit for eating.
Example: When packets of potato chips or other oily snacks are kept open for a long time; their taste and smell become bad. The oily food is no longer safe to eat.
Why does a compass needle get deflected when brought near a bar magnet?
Compass needle is a bar magnet when it is brought near a bar magnet, its magnetic field interacts with the magnetic field line of the bar magnet. Therefore deflection occurs in the compass needle.
Compass needle is a bar magnet when it is brought near a bar magnet, its magnetic field interacts with the magnetic field line of the bar magnet. Therefore deflection occurs in the compass needle.
See lessList the properties of magnetic field lines.
The properties of magnetic field lines are: (a) Magnetic field lines emerge from the north pole. (b) They merge at the south pole. (c) The direction of field lines inside the magnet is from the south pole to the north pole. (d) Magnetic lines do not intersect with each other.
The properties of magnetic field lines are:
(a) Magnetic field lines emerge from the north pole.
(b) They merge at the south pole.
(c) The direction of field lines inside the magnet is from the south pole to the north pole.
(d) Magnetic lines do not intersect with each other.
See lessWhy don’t two magnetic field lines intersect each other?
Two magnetic lines never intersect because if two field lines of a magnet intersect, then at the point of intersection, the compass needle points in two different directions which is not possible at same time a needle shows to different directions. Hence, they never interact.
Two magnetic lines never intersect because if two field lines of a magnet intersect, then at the point of intersection, the compass needle points in two different directions which is not possible at same time a needle shows to different directions. Hence, they never interact.
See lessConsider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.
Inside the loop = Pierce inside the table Outside the loop = Appear to emerge out from the table For the downward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside tRead more
Inside the loop = Pierce inside the table
Outside the loop = Appear to emerge out from the table
For the downward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop. Similarly, for the upward direction of current flowing in the circular loop, the direction of magnetic field lines will be as if they are emerging from the table outside the loop and merging in the table inside the loop.
See lessChoose the correct option. The magnetic field inside a long straight solenoid-carrying current
(d) The magnetic field inside a long, straight, current-carrying solenoid is uniform. Therefore, it is the same at all points inside the solenoid.
(d) The magnetic field inside a long, straight, current-carrying solenoid is uniform. Therefore, it is the same at all points inside the solenoid.
See lessWhich of the following property of a proton can change while it moves freely in a magnetic field?
(c) and (d) When a proton enters an area of magnetic field, it experiences a magnetic force. As a result of the force, the path of the proton becomes circular. Therefore, its velocity and momentum change.
(c) and (d)
When a proton enters an area of magnetic field, it experiences a magnetic force. As a result of the force, the path of the proton becomes circular. Therefore, its velocity and momentum change.
See lessA positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is
(d) The direction of the magnetic field can be determined by applying Fleming’s left hand rule. According this rule, if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the cRead more
(d) The direction of the magnetic field can be determined by applying Fleming’s left hand rule. According this rule, if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the direction of magnetic field. As the direction of a positively charged alpha particle is towards west, the direction of current will be the same i.e., towards the west. If the direction of magnetic force is towards the north. Hence, according to Fleming’s left hand rule, the direction of the magnetic field will be upwards.
See lessState Fleming’s left-hand rule.
Fleming’s left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the diRead more
Fleming’s left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each other, then the thumb points towards the direction of the magnetic force, the centre finger gives the direction of current, and the forefinger points in the direction of magnetic field.
See lessWhat is the principle of an electric motor?
The principle of an electric motor is based on the magnetic effect of current. A current-carrying loop experiences a force and rotates when placed in a magnetic field. The direction of rotation of the loop is determined by Fleming's left-hand rule.
The principle of an electric motor is based on the magnetic effect of current. A current-carrying loop experiences a force and rotates when placed in a magnetic field. The direction of rotation of the loop is determined by Fleming’s left-hand rule.
See less