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1.

1- A straight wire is part of a circuit that has a resistance (R) of 0.50 Ω. The wire is 0.20 m long and moves at a constant speed of 7.0 m/s perpendicular to a magnetic field of strength 8.0×10-2 T .What EMF is induced in the wire

a)

0.11 V

b)

0.11 N

c)

11 V

d)

1.1 V

2.

2- what is the unit of EMF?

a)

$\frac{N.m}{A.s}$

b)

$\frac{N.s}{A.m}$

c)

$\frac{A.m}{N.s}$

d)

$\frac{J}{C}$

3.

3-Q.

In the figure , what is the direction of the emf and induced current ?

a)

both are up

b)

emf--> down

induced current down

c)

emf--> left

induced current down

d)

both are down

4.

4-A straight wire is part of a circuit that has a resistance (R) of 0.50 Ω. The wire is 0.20 m long and moves at a constant speed of 7.0 m/s perpendicular to a magnetic field of strength 8.0×10-2 T .What is the current through the wire if EMF = 0. 11v

a)

0.22 A

b)

0.022 A

c)

0.22 mA

d)

2.2A

5.

5-

B=0.30T

v=20m\s

L=3m

find emf

a)

180v

b)

18V

c)

0.18v

d)

18N

6.

6-.If the average power used over time by an electric light is 75 W, what is the peak power?

a)

150w

b)

37.5w

c)

150Kw

d)

53.0w

7.

7-Electric generator It is a device that convert

a)

Mechanical energy to sound energy

b)

sound energy to mechanical energy

c)

mechanical energy to electrical energy

d)

electrical energy to mechanical energy

8.

when a wire or a conductor is produced EMF and induced current ?

a)

relative motion between a conductor and magnetic filed

b)

relative motion between a conductor and electric file filed

c)

when a wire moves parallel to a magnetic field

d)

when a wire length is the half of the magnetic filed magnitude

9.

what is the component of the Ac generator numbered by (5)

a)

slip-ring

b)

electrical input

c)

brush

d)

armature

10.

A step-up transformer has a primary coil consisting of 200 turns and a secondary coil consisting of 3000 turns. The primary coil is supplied with an effective AC voltage of 90.0 V the current in the secondary circuit is 2.0 A. What is the current in the primary circuit?

a)

300A

b)

30A

c)

0.3A

d)

0.03A

11.

If the number of turns of the secondary winding is greater than the number of turns of the primary winding (Ns > Np) the transformer is :

a)

step-up

b)

step-down

c)

isolation

d)

this is not a transformer

12.

a transformer with 160 w have an input potential difference of 10v , and an output current of 5A

what is the output to input

a)

$\frac{16}{5}$

b)

$\frac{5}{16}$

c)

$\frac{3}{5}$

13.

The magnetic field due to the induced current opposes the change in the magnetic flux that induces the current this statement called

a)

Newton’’s Third Law of Motion القانون الث

b)

Lenz’s Law

c)

Ohm’s Law

d)

Law of reflection

14.

A generator develops a maximum potential difference of 233 V

A generator develops a maximum potential difference of 2.3 A

what is the effective potential difference ?

a)

1.01V

b)

542.89v

c)

164.75v

d)

329v

15.

يمتاز محول 150 وات بفرق جهد دخل 9فولت و تيار خرج 5 امبير . ما نسبة الجهد الخارج إلى الجهد الداخل ؟

a)

ثلاثة الى واحد

b)

ثلاثة إلى عشرة

c)

عشرة إلى ثلاثة

d)

واحد الى ثلاثة

16.

calculate the wavelength of a wave has a frequency of $4.1\times10^{14\ \ }Hz$

a)

$4.31\cdot10^{-7}m$

b)

$1.23\cdot10^{23}m$

c)

1266 m

d)

273m

17.

the energy carried by an electromagnetic waves is propotional to ?

a)

the square of the amplitude of the electric field

b)

area the wave crosses

c)

the square root of the amplitude of the magnetic field

d)

the half of the amplitude of the electric field

18.

which type of electromagnetic wave is used for measuring temperature of buildings ?

a)

infrared waves

b)

uv waves

c)

microwaves

d)

radi waves

19.

when the antenna is more efficient ? so mere potential difference across

a)

when an antenna is one-half the length of the waves it is designed to detect

b)

when an antenna is one-forth the length of the waves it is designed to detect

c)

forth the length of the waves it is designed to detect

d)

forth the length of the waves it is designed to detect

when an antenna is one-fifth the length of the waves it is designed to detect

20.

which order is the correct order from greatest wavelength to shortest wavelength

a)

radio wave

microwave

infrared

visible light

uv

x-rays

gamma rays

b)

gamma rays

x-rays

visible light

microwave

infrared

radio wave

microwave

c)

radio wave

microwave

infrared

gamma rays

X-ray

UV

d)

Uv

X-ray

radio wave

microwave

infrared

gamma rays

21.

Electromagnetic waves are transverse waves. Both electric and magnetic fields oscillate ------------to the direction the wave travels.

a)

perpendicular

b)

horizontal

c)

vertical

d)

parallel

22.

calculate the frequency of a wave has a wavelength $2.2\times10^{-2\ }$ m

a)

$1.36\times10^{10}Hz$

b)

$7.333\times10^{-11}Hz$

c)

6000000Hz

23.

which type of electromagnetic wave is used for GPS

a)

microwaves

b)

infrared

c)

UV

d)

X-rays

24.

Electromagnetic waves are coupled, oscillating electric and magnetic fields that propagate through ?

a)

space and matter

b)

only matter

c)

space

d)

water only

25.

A parabolic dish antenna reflects and focuses signals off its surface and into?

a)

horn

b)

dish

c)

amplifier

last revision

Total questions: 25

Worksheet time: 13mins

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