6.0V, 16Ω
6.0V, 1Ω
1.5V, 4Ω
1.5V, 1Ω
Correct answer is D
Since all the cells are connected in parallel, the effective e.m.f. is just that of one single cell. Which means e.m.f. = 1.5V
However, the effective internal resistance adds as parallel arrangement given as
1/r = 1/r1 + 1/r2 + 1/r3 + 1/r4
= 1/4 + 1/4 + 1/4 + 1/4
= 1Ω
∴ r = 1Ω
Answer = 1.5V, 1Ω
Steel is more suitable for permanent magnet than iron because the former
is easily demagnetized by shaing vigorously
is an alloy of many metals
is easily magnetized by alternating current through one cycle
retains magnetism more than iron
Correct answer is D
No explanation has been provided for this answer.
Which of the following electromagnetic waves is least energetic?
Infra-red rays
X-rays
Ultra-violet rays
Gamma rays
Correct answer is A
No explanation has been provided for this answer.
An astronomical telescope is said to be in normal adjustment when the
eye is accommodated
focal length of objective lens is longer than that of eye piece
final image is at the near point of eye
final image is at infinity
Correct answer is D
No explanation has been provided for this answer.
0.33
0.50
0.67
0.75
Correct answer is D
Refractive index
= \(\frac{Sin i}{Sin r}\) = \(\frac{\text{Vel. of light in air}}{\text{vel. of light in glass}}\)
= \(\frac{Sin i}{Sin 30^o}\)= \(\frac{3.0 \times 10^8}{2.0 \times 10^8}\)
= Sin i = \(\frac{(3.0 \times 10^8 \times Sin 30^o)}{2.0 \times 10^8}\)
= Sin i = \(\frac{(3.0 \times 10^8 \times 0.5)}{2.0 \times 10^8}\)
= \(\frac{1.5}{2}\)
= 0.75