Physics- P7 Part B

1. To increase the field strength of solenoid, add an ... block in the centre of the coil- ... becomes an induced magnet. If current is stopped, the magnetic field disappears (4)
3. A ... is a coil of wire. It increases the magnetic field strength because the field lines around the wire line up with each other. The magnetic field inside the ... is strong and uniform. A ... with an iron core is called an Electromagnet (8)
4. When a ... flows through a wire, magnetic field is created around it. Changing the direction of the ..., changes the direction of the magnetic field- (Right hand thumb rule). The strength of a magnetic field changes depending on the size of the ... (7)
8. Uses of electromagnets: These are used for electric starters of motors. Close it and current flows, and attraction within the circuit happens and motor is turned on (8, 2, 8)

2. The ... is when a current-carrying wire is put between magnetic poles, the magnetic field interacts around wire, with magnetic field its placed in. A force is exerted on each conductor and the wire can move (5, 6)
3. ... of forces increases with ... of magnetic field. Force also increases with amount of current passing through the wire (8)
6. For a full ... the wire has to be 90 degrees to the magnetic field. At parallel no ... will be felt. At other angles, some ... will be felt (5)
7. Uses of electromagnets: These attract and pick up magnetic objects. Using electromagnets means it can be turned on to pick something up, and off to drop something e.g. A scrap yard (6)

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