2119

Physics Electromagnetic Induction Level: High School

The 10cm-wide ,zero-resistance slide wire shown in the figure which is shown at ‘click here’ is pushed toward the 2.0 ohm resistor at a steady speed of 0.50 m/s .The magnetic field strength is 0.50 T .

a) How big is the pushing force ?

b) How much power does the pushing force supply to the wire ?

c) What are the direction and magnitude of the induced current ?

d) How much power is dissipated in the resistor ?




2118

Physics Magnetism,Magnetic Effects Of Current Level: High School

Force on a moving charge in a magetnic field

The uniform 30 m T magnetic field in the figure which is shown at ‘click here’ points in the positive z-direction , an electron enters the region of magnetic field with a speed of 5.0 x 10^6 m/s and at an angle of 30 degrees above the xy-plane . Find the radius r and the pitch p of the electron’s spiral trajectory .



2117

Physics Magnetism,Magnetic Effects Of Current Level: High School

Ampere's Law

Consider a long, cylindrical wire of radius R carrying a current , (i), distributed uniformly over the cross section . At what two distances from the axis of the wire is the magnetic field strength due to the current , equal to one-half the value of the surface ?



2116

Physics Electromagnetic Induction Level: High School

A square wire loop with 2-3m sides is perpendicular to a uniform magnetic field . with half the area of the loop in the field . The loop contain a 2.0 V battery with negligible internal resistance . If the magnitude of the field varies with time according to B = (0.042T)-(0.87T/s)t, what is the total emf of the circuit ?



2115

Physics Relativity Level: High School

The fundamental interaction responsible for the stability of a nucleus is the

a) Gravitational interaction

b) Newton’s laws

c) Strong gor nucleus interaction

d) Weak interaction

Coulomb force

c) Strong gor nucleus interaction



2114

Physics Relativity Level: High School

According to Einstein’s special theory of relativity , when compared to an identical clock at rest, a clock moving with constant velocity will run

a) slow

b) fast

c) at the same rate

d) alternately fast and

a) slow



2113

Physics Relativity Level: High School

When it comes near a heavy nucleus , a gamma ray , which is high energy photon can “disappear”, and in its place three will be produced an electron and a positron, which both have mass , This pair production is an example of

a) time dilation

b) length contraction

c) the equivalent of mass and energy

d) the principle of relativity

e) None of the above

c) the equivalent of mass and energy



2112

Physics Relativity Level: High School

The prediction of special relativity that the length of a moving object will be shortened in the direction of motion is ?

a) time dilation

b) length contraction

c) the equivalence of mass and

d) the principle of relativity

e) None of the above

b) length contraction



2111

Physics Modern Physics Level: High School

Nucleus

The half-life of carbon-14 is 5730 years . The time for ¾ of a sample of carbon-14 to decay is

a) 350 years

b) 2865 years

c) 11460 years

d) 17190 years

e) none of the above




2110

Physics Modern Physics Level: High School

Nucleus

The mass of an atom of helium-4(Z=2) is less than the mass of two free protons and two free neutrons because of ?

a) nuclear fusion

b) nuclear fission

c) neutron

d) nuclear emission

e) binding energy

e) binding energy



2109

Physics Modern Physics Level: High School

Nucleus

When radium-223 (Z=88) decays to radon-219 (Z=86) , the other particle emitted is a(n)

a) alpha particle

b) beta particle

c) gamma ray

d) x-ray

e) none of the above




2108

Physics Modern Physics Level: High School

Nucleus

Radioactive decay is involved in which of the following ?

a) Keeping of the Earth’s interior hot

b) Making smoke detectors work

c) Supplying energy for interplanetary space

d) Making the sun shine

b) Making smoke detectors work



2107

Physics Modern Physics Level: High School

Nucleus

How do isotopes of a given element differ ?

a) They have different mass numbers

b) They have different electron numbers

c) They have different atomic numbers

d) They have different quantum

e) None of the above

a) They have different mass numbers



2106

Physics Modern Physics Level: High School

The continuous part of an x-ray spectrum of an atom occurs because

a) of the photon absorption

b) of the photoelectric effect

c) electrons in the atom make transitions to lower energy

d) of the uncertainty principle

e) of rapid deceleration of the bombarding electrons

c) electrons in the atom make transitions to lower energy



2105

Physics Modern Physics Level: High School

Photoelectric effect

When the frequency of light is decreased in a photoelectric effect , the energy of the emitted electrons

a) increase

b) decrease

c) stays the same

d) becomes more quantized

e) become less quantized


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