Physics Questions and Answers
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
2.5\(\Omega\)
5.0\(\Omega\)
8.0\(\Omega\)
10.0\(\Omega\)
Correct answer is B
r = resistance of the galvanometer
l = current through galvanometer = 20mA or 0.02A
V1 = p.d across the galvanometer = I X r = 0.02 X r
: V1 = 0.02r
V2 = p.d across the multiplier = 8 - 0.02r
R = resistance of the multiplier = 395Ω
where R = \(\frac{V}{I}\)
--> 395 = \(\frac{8−0.02r}{0.02}\)
CROSS MULTIPLY
8−0.02r = 395 * 0.02
8−0.02r = 7.9
--> 0.02r = 8 - 7.9
∴ r = \(\frac{0.1}{0.02}\)
= 5Ω
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