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.
120
100
1000
1200
Correct answer is B
For the transformer, V ∝ ∩
=> V s ∝ ∩s; Vp ∝ ʌp
=> Vp/Vv = ∩p/∩s, therefore 120/1200 = ∩p/1000
therefore ∩p * 1200 = 120 * 1000
∩p = 120*1000/1200 = 100
A/√2
2/√A
2 A
√2 A
Correct answer is B
If I = 2 Sin wt; but in a.c. circuit current I = I0 Sin wt; thus comparing the two equations, it implies that I0 = 2A; Again, the root means square (I(rms)) of an a.c. current is the value of the d.c. current that will dissipate the same amount of heat in a given resistance as the a.c.
and I(rms) = I0/√2 = 2.0A/√2
I and IV only
I and III only
II and IV only
II and III only
Correct answer is B
Electricity conduction through gases is usually done under low pressure (I) and high voltage (III). Thus /B/
The particles emitted when \( ^{39}_{19}K \text{ decay to } ^{39}_{19}K \) is
gamma
beta
electron
alpha
Correct answer is A
3919K 3919K.
Since neither the mass number (39), nor the atomic number (19) is affected by the emission,the particles emitted can only be gamma ray, which is not a charge particle, but simply a radiation.
2.0Ω
1.0Ω
2.5Ω
1.5Ω
Correct answer is A
let the internal resistance of the cell = r,
therefore E = I (R+r)
(i) E = 0.4(4+r), (ii) E = 0.2 (10+r)
therefore 0.4 (4+r)= 0.2 (10+r)
1.6 + 0.4r = 2.0 * 0.2r
0.4r - 0.2r = 2.0 - 1.6
therefore 0.2r = 0.4 => r = 0.4/0.2 = 2Ω
therefore r = 2Ω