The figure illustrates a closed electric circuit when the switch (K) is opened so ................?

The figure represents a part from a closed electric circuit. The equivalent resistance of the shown combination equals ..................?

In the shown closed electric circuit, the ratio between $$\frac{I_3}{I_2}$$ = ...............?

The figure represents lwo straight current carrying parallel wires (A) and (C) which of the following choices represents the intensity and the direction of the current in wire (C) that produces a neutral point at point (Z) ?

The graph represents the relation between the magnetic flux density (B) at the mid-point of the axis of a number of spiral coils (L,M,N and O) and the current intensity (I) passing through them, if you know that all the coils have the same number of turns and their cores have the same magnetic permeability, then the coil that has the smallest length is coil .................?

Using the illustrated in both figures (1) and (2) . Which of the following relations represent correctly the relation between magnetic flux density (B) at points C₁ and C₂ ?

In the shown figure:

If wire (x) is affected by a magnetic force per unit length of (2 × 10⁶ N/m) rightward due to the effect of the magnetic flux resulted due to the passing current through wire (y) then the magnitude and direction of $$\left(I\right)$$ are ..............? $$\left(\mu=4\ \pi\times10^{-7}\ T.m.A^{-1}\right)$$

A galvanometer of maximum reading 0.01 A is connected in series to a resistor of $$2000\ \Omega$$ to convert it into voltmeter as shown in the figure so that the maximum potential difference that can be measured by the voltmeter was 20.5 V . In order to measure a maximum potential difference 10.25 V the $$2000\ \Omega$$ resistor must be replaced by a resistor of resistance equal to ..................?

In the opposite figure:

If the shunt is replaced to increase the sensitivity of the device keeping the current ( $$I$$ ) constant. Which of the ratios below increases?

At the moment of moving the magnet in either of the two direction (1) and (2) with the same speed, e.m.f of 0.5 V_B is induced in the coil . Which of the following choices is correct at the moment of moving the magnet?

The figure illustrates a magnet moving with velocity (v) to the left towards a solenoid connected to a galvanometer . But there is no current induced in the coil, this is due to that the solenoid moves ...............?

The figure represents a wire (AB) that has a resistance of $$\left(0.5\ \Omega\right)$$ moving perpendicular to a magnetic flux of density (0.2 T) . In order to obtain an induced current of 0.1 A at the moment of the wire motion, the wire must move with a velocity equal to .............?

(Neglect the resistance of the connection wires)

The opposite figure represents a uniform magnetic field acting on wire (PQ) that is placed in the same plane of the page. If the direction of the induced current is from (Q) to (P) , so the direction of motion of the wire is towards ............?

AC dynamo, it's coil consists of 200 turns each area 0.02 m² , rotates in a magnetic field of flux density 0.02 T by a rate of 6000 rotations per minute, then the effective value of the induced e.m.f equals .............?

The graph represents the relation between the change in the magnetic flux $$\left(\phi_m\right)$$ that is intercepting a coil versus time (t) . If you know that the coil consists of 200 turns, then the average induced e.m.f in the coil within the time interval of 0.2 s represented in the graph equals ...............?

Two adjacent coils the mutual inductance between them is (2 H) . The graph represents the relation between the change of the electric current (I) in the primary coil with time (t) . Which one from the following graphs represents the relation between the induced electromotive force in the secondary coil with time ?

If the shunt resistor in the hot wire is replaced by another of smaller value while keeping the effective value of the electric current flowing through the circuit constant then ..............?

The figure shows an oscillatory circuit containing a capacitor of capacitance $$200\ \mu F$$ . What is the value of the inductance of the coil (L) required to obtain a current of frequency that equals 100 Hz when switching the key from position (1) to (2) ?

The graph of effective current ( $$I$$ ) versus frequency (x) for an alternating current circuit in which a non-inductive ohmic resistor, an induction coil of negligible ohmic resistance and a capacitor of variable capacitance are connected in series is shown in the opposite figure. So in the figure the points where the potential difference between the two ends of the capacitor is greater than the potential difference between the two ends of the coil are ....................?

A photon has frequency (4.2 × 10¹⁴ Hz ) then its linear momentum is equal to ...............?

(Given that : $$c=3\times10^8\ m.s^{-1}\ ,\ h=6.625\times10^{-34}\ J.s$$ )

A cathode ray tube works at a potential difference 2000 V , while another identical tube works at a potential difference 8000 V , then the ratio between the wavelength of the associated wave to the emitted electrons from the first tube cathode and the wavelength of the associated wave to the emitted electrons from the second tube cathode equals ..............?

Which of the following graphs represents the relation between the energy of a photon (E) in the radiation emitted from a blackbody and its wavelength $$\left(\lambda\right)$$ ?

From the figure, spectra (1) and (2) respectively are ............ , ..............

The figure represents the relation between the intensity of X-rays radiation produced from a Coolidge tube operated at potential difference (V) and its wavelength. On increasing both of the filament current intensity and the potential difference between the cathode and the anode . Which choice is the correct answer ?

The phase difference between two laser rays after reflection from an object equals $$2\ \pi$$ then the path difference between the two rays equals .............?

The figure shows the production of a hologram by using laser. Which choice is considered the reference rays ?

The figure illustrates laser photon production from the mixture of two gases (He) and (Ne) knowing that both levels E₂ and E₃ are metastable levels , which transmission causes a laser photon emission ?

Which of the following simple electric circuits in the choices represents the combination of the opposite logic gates ?

According to the given figure :

The resistance of the diode in case of forward connection is $$2\ \Omega$$ and its resistance in backward (reverse) connection is infinite. Which of the following choices is the correct answer to obtain the largest consumed power in the electric lamp ?

In the transistor circuit, if the current of the emitter is 120 times as that of the base , then $$\alpha_e$$ equals ...........?

Which graph from the choices illustrates the relation between the electrical conductivity for a pure semiconductor crystal and a copper wire as temperature changes ?

In the electric circuit, if the voltmeter reading when the slider of the rheostat is at (A) was 12 V and when the slider is moved to point (B) , the voltmeter reading was 3 V . The value of the resistance taken from the rheostat at (B) is ............?

The following figures illustrate four wires of different materials, using the data on the figures, which wire material has greatest conductivity at the same temperature ?

A current of intensity (I) passes in a current-carrying coil which is placed in a magnetic field of flux density (B) , where the coil plane makes an angle 60° with the direction of the magnetic flux. If the value of magnetic dipole moment in (A.m²) is 4 times as the value of the magnetic torque acting on the coil in (N.m) then the value of the magnetic flux density (B) equals .............?

A wire (X) that carries a current of intensity (I) is placed in different magnetic fields as shown in the following figures.

Which of the following choices represents the correct arrangement of the values of the magnetic force acting on the wire according to each figure ?

In the ohmmeter circuit shown in the figure, when another resistance is connected to the unknown resistance (R_x) in series, the pointer deflects to 3/5 from the scale of the galvanometer . Then the value of the connected resistance is ..............?

You have DC electric motor consists of a single coil that started its motion from a position parallel to the flux lines as in the figure, after the coil rotates by 60° clockwise from the shown position, therefore ...............?

The shown graph represents the change of magnetic flux $$\left(\phi_m\right)$$ that intercepts a dynamo coil of 200 turns and the time (t) . Then the instantaneous e.m.f that is produced in the coil after 0.1 ms from the zero position equals .............?

In the opposite figure, an inductive coil of negligible ohmic resistance if $$\frac{1}{4}$$ of the coil is cut and the rest of the coil is connected to the circuit without changing any other factors , the correct choice is .................?

From the given date in the figure, the value of the electromotive force of the source of alternating current equals ..............?

The figure represents two capacitors (1) and (2) capacitor (1) is charged with a charge of $$60\ \mu C$$ and capacitor (2) is unchanged. After closing the switch (K) , which of the following choices represents the charge on the two capacitors (1) and (2) ?

In order to examine a virus of 30 nm dimensions, a potential difference (V) is used, so in order to examine another virus of dimensions 15 nm , the potential difference must be .................?

A photon hits an electron in the ground state of hydrogen atom, as a result the electron moved to excitation level (N) . (Given that : $$c=3\times10^8\ m.s^{-1}\ ,\ h=6.625\times10^{-34}\ J.s\ ,\ e=1.6\times10^{-19}\ C$$ ) , which of the choices expresses the incident photon's wavelength ?

The figure illustrates, a straight current-carrying wire. Which of the following choices represents correctly the relation between the magnetic flux densities (B_Y and B_z) due to the current (I) in the wire at points (Y) and (Z) that lie in the same vertical plane with the wire?

Each of the following figures represents two concentric metallic rings in the same plane carrying electric currents . In which one of them the resultant magnetic flux density at the common centre is higher?

The figure illustrates, two parallel straight wires (1 , 2) carrying currents $$\left(I_1\ ,\ I_2\right)$$ respectively . To make point (y) represent a neutral point for the two magnetic fields , the intensity and the direction of current $$I_2$$ must be ...............?

A rectangular coil carrying a current is placed in a magnetic field where its plane makes an angle 60° with the direction of the magnetic field lines . If the value of the magnetic torque acting on the coil in (N.m) equals the value of the magnetic dipole moment of the coil in (A.m²) the magnetic flux density equals ................?

According to the data in the figure, the potential difference measured by the voltmeter = ...............?

The opposite table represents different values of shunt resistance that are used one at a time with the same galvanometer to form direct current ammeters W, X ,Y and Z , so what is the correct order of these ammeters according to their sensitivities ?

One of the military applications of laser is for destroying missiles, this is due to ................ ?

The emergence of laser beam from the semi -transparent mirror in He-Ne laser starts depending on .............. ?

The amplification of the number of photons produced by stimulated emission in He-Ne laser is due to the collisions of .................?

An electric current of intensity (I) flows through a hot-wire ammeter. If the current through the hot-wire ammeter increases to (2I) ..............?

An oscillating circuit consists of a coil of inductance 1 H and a capacitor of $$3.5\ \mu F$$ so the frequency of the oscillating circuit current is

Three capacitors $$\left(12\ \mu F\right)$$ , each of capacitance where connected to a DC source of (20 V) with two different methods as in figures (A) and (B)

So the ratio of the charge accumulated on each capacitor in circuit (A) to that in circuit (B) $$\left(\frac{Q_A}{Q_B}\right)$$ equals ...........?

The figure shows a simple electric circuit that contains three switches (X , Y and Z) working as inputs of a logic circuit , while the lamp gives the output. The group of logic gates that is represented by this simple electric circuit is ...........?

The electric circuit shown in the figure represents a transistor used as a switch, so on increasing the value of R_B to double its value. Which of the following choices correctly describes what happens to the value of V_cc ?

The current gain $$\left(\beta_e\right)$$ for a transistor = 150 , so $$\left(\alpha_e\right)$$ = .............?

The value of intensity of the electric field established inside the diode at a certain temperature becomes constant when .............?

The scientific principal of using X-rays to study the crystalline structure of solids depends on ...............?

In Cooling tube tungsten ₍₇₄₎W was used as target to produce X-rays , so that one of the characteristic wavelength of X-rays radiation was 1.8 × 10^-11 m so on replacing the target With another one made of molybdenum ₍₄₂₎Mo , one of the characteristic wavelength of X-rays radiation probably equals ...............?

Two identical magnets (1) , (2) were placed at the same distance from a solenoid as shown in the figure. One moving each of the magnets with the same speed simultaneously towards the two terminals of the solenoid and along its axis, it is noticed that the pointer of the galvanometer doesn't deflect. This is due to ...............?

A straight wire of length $$\left(\iota\right)$$ moves with velocity (v) inclined to a magnetic field of flux density (B) with an angle (30°) to the direction of the field, so an induced electromotive force is generated in it . To increase the electromotive force generated in it to the double............?

A single coil DC electric motor, when the coil's plane is perpendicular to the magnetic flux lines, which of the following quantities does not equal zero ?

In the figure the wire (L) is able to move in the same plane of the page through a magnetic field perpendicular into the page.

Which of the following choices is correct ?

An alternating current dynamo produces a current of frequency 50 Hz , so the time for the current to reach a value equal to its effective value for the first time from the perpendicular position = ...............?

A metallic wire moves with constant velocity (v) upwards in the plane of the page and is affected by a magnetic field perpendicular into the plane of the page. Which figure illustrates the drift of the electric charges inside the wire during its motion ?

Two coils (X) , (Y) the number of turns of coil (X) is 500 turns and the number of turns of coil (Y) is 1000 turns. The graph represents the change of magnetic flux $$\left(\Delta\phi_m\right)_Y$$ through coil (Y) when the current (I_x) changes through coil (X) . So the mutual inductance between the two coils equals ...............?

In the shown electric circuit :

Which readings of those voltmeters are equal ?

In the shown closed electric circuit : we can conclude that ..............

The figure shows a part of a closed electric circuit, then the value (I) = ..................?

The figure represents four aluminium wires. Which wire has the least electric resistance ?

A proton moves at a velocity of 3 × 10⁶ m/s so the wavelength of its accompanied wave is = ...............

( $$m_p=1.67\times10^{-27}\ kg\ ,\ h=6.625\times10^{-34}\ J.s$$ )

The figure illustrates Planck's distribution curve for a hot body. If the body is left to cool down, the curve changes to figure .................?

A potential difference is applied in an electron microscope to give the electrons a velocity of 18 × 10⁶ m/s in order to see a virus of length $$300\ A^{\circ}$$ . Knowing that plank's constant = 6.625 ×10^_34 J.s and the mass of electron= 9.1 × 10^-31 kg , so .................?

The graph represents the relation between the magnetic force acting on a straight wire of length $$\left(\iota\right)$$ placed in a uniform magnetic field of flux density (B) and the change of angle $$\left(\theta\right)$$ which is the angle between the wire and the field if $$\frac{F_2}{F_1}=\frac{2\ \sqrt[]{3}}{3}$$ ,

So the value of angle (X) = ................

The following figure represents an ohmmeter circuit containing a galvanometer that the resistance of its coil is (R_g) when it is connected to an external resistance (R_x) that equals (15 R_g ) the pointer of the galvanometer deflects to 1/5 of its full current scale deflection. Therefore the value of the resistance taken from the rheostat (R_v) =

A metallic straight wire (yx) of length 0.2 m whose electric resistance is $$1\ \Omega$$ moves at velocity of 3 m/s perpendicular to the direction of magnetic field of flux density 0.5 T on two rails of negligible resistance that are connected with two resistors $$6\ \Omega\ ,\ 3\ \Omega$$ as shown in the figure. Then the potential difference across the resistor $$\left(3\Omega\right)$$ during moving the wire equals ...............?

The figure illustrates a part of a closed electric circuit. Then the resistance (R) equals ..............?

The figure illustrates a call with internal resistance (r) , when it is connected to 2 different circuits (each individually) , the ammeter reading is (1.2A) in the first circuit and (1 A) in the second circuit. So the value of the internal resistance of the cell = ...............

Two parallel straight wires A and B carry electric currents of intensities 2 A and (I) respectively in opposite direction. If the normal separating distance between the two wires is 5 cm and the common length between them is 10 cm . The two wires are affected by a mutual magnetic force of 2.4 × 10^-6 N , then the value of (I) should be ................... and the type of the mutual force is ....................

(Take : $$\mu=4\pi\times10^{-7}\ Wb.A^{-1}.m^{-1}$$ )

According to the given figure , the capacitance of the capacitor (C) which causes maximum lightning of the electric lamp equals ............. Farad

X-ray photon of wavelength (4 × 10^-9 m) losed 2% from its energy when it collided with a static electron, so the wavelength of the scattered photon after collection becomes ................. ?

(Given that : $$c=3\times10^8\ m.s^{-1}\ ,\ h=6.625\times10^{-34}\ J.s$$ )

The longest wavelength of the visible spectrum emitted from the hydrogen atom = ................. $$A^{\circ}$$

(Given that : $$c=3\times10^8\ m.s^{-1}\ ,\ h=6.625\times10^{-34}\ J.s\ ,\ e=1.6\times10^{-19}\ C$$ )

The graph represents the change in the magnetic flux $$\left(\phi_m\right)$$ that intercepts a dynamo coil of 200 turns versus time (t) . So , the average induced e.m.f in the dynamo coil during the shown 1/4 cycle equals ...............?

In the AC circuit in the figure, the total potential difference for the circuit ................?

(The source frequency = $$50\ Hz\ ,\ \pi=\frac{22}{7}$$ )

Three coils of negligible ohmic resistance are connected as in the figure with a source of alternating current . So the value of the unknown self induction coefficient (L) which allows an electric current of 3 A to pass in the circuit is ...............

( Neglect the mutual induction between the coils )