Which of the following statements about electric potential energy is not correct?
The electric potential energy of a positively charged particle increases when it moves to a point of higher potential
The electric potential energy of a negatively charged particle increases when it moves to a point of lower potential
The electric potential energy of a positively charged particle decreases when it moves to a point of higher potential
The work done in taking a charged particle around a closed path in an electric field is zero.
Correct answer is B
The potential energy for a positive charge increases when it moves against an electric field
And decreases when it moves with the electric field;
The opposite is true for a negative charge. Unless the unit charge crosses a changing magnetic field, its potential at any given point does not depend on the path taken.
0.90A
0.39A
0.30A
0.01A
Correct answer is C
Given Data: Emf = 1v, r = 2 ohms, R = 3 ohms, I = ?
3 resistance in parallel = \(\frac{1}{r_1}\) + \(\frac{1}{r_2}\) + \(\frac{1}{r_3}\)
\(\frac{1}{r_T}\)= \(\frac{1}{2}\) + \(\frac{1}{2}\) + \(\frac{1}{2}\)
\(\frac{1}{r_T}\) = \(\frac{1+1+1}{2}\)
\(\frac{1}{r_T}\) = \(\frac{3}{2}\)
cross multiply
r\(_T\) = \(\frac{2}{3}\) or 0.67
E = I(R+r)
1 = I(3+0.67)
1 = I(3.67)
1 ÷ 3.67 = I
0.27 = I
: I ≈ 0.30A
maximum motor force if the current reverses its direction
no motor force of it is parallel to the field
no motor force if it is perpendicular to the field
a motor force with constant direction if either the current or the magnetic field is reversed
Correct answer is B
The greatest force is experienced when the conductor is at right angle to the field.
I.e at perpendicular or Ø = 90°
photoelectric effect
heisenberg's uncertainty principle
compton effect
wave-particles paradox
Correct answer is A
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material
ferrite substance
paramagnetic substance
ferromagnetic substance
diamagnetic substance
Correct answer is A
Ferrite magnets are non-conductive aferromagnetic ceramic compounds derived from iron oxides such as Haematite (Fe203) or Magnetite (Fe304) and other metal oxides such as Barium and Strontium.
Ferrite is a polycrystal, sintered material with high electrical resistivity. The high resistance of ferrite makes eddy current losses extremely low at high frequencies.