The resultant of two forces 12N and 5N is 13N. What is the angle between the two forces?
0o
45o
90o
180o
Correct answer is C
R2 - P2 + Q2 = 122 + 52
= 144 + 25 = 169
∴R = √169 = 13N
∴ angle between the forces is 90o
The dimension of electromotive force are?
ML2T-3I-1
ML2T-3I-2
M2LT-2I-1
M2L2T-1I-1
Correct answer is A
Electrical work W = QE,
Where Q is the quantity of change and E is the electromotive force.
∴ E = W = FxDQ_It
Where D is the displacement,I = current and t = time
But dimension of force,
= unit of mass x unit of Acceleration
= unit of mass xunit of velocityunit of time
= unit of mass x unit of displacement__unit of time x unit of time
ML/T2 = MLT-2
∴ Dimension of emf E
= MLT-2L = ML2T-3I-1__IT
5.4 min
10.8 min
15.0 min
20.0 min
Correct answer is A
From faradays law, M = itz
But mass, M = volume x density
and volume = cross sectional area x thickness
M = 118.8cm2 x 10-6 x 9 x 103
∴ 118.8cm2 x 10-6 x 9 x 103 = 10 x t x 3.3 x 10-7
∴ (118.8 x 9) x 10-7 = 10 x t x 3.3 x 10-7
∴ t = \(\frac{118.8 \times 9}{ 3.3}\)
t = 324 seconds
Convert to minutes by dividing by 60
t = \(\frac{324}{60}\)
t = 5.4 sec
from the diagram above, the inductive reactance and the resistance R are respectively
50Ω and 45Ω
25Ω and 51Ω
20Ω and 50Ω
10Ω and 50Ω
Correct answer is D
The inductive reactance is given as
Xl = 2πfl
= 2 x 50/π x 0.1
= 10Ω
Again from ohms law,
R = V/I = 75/1.5 = 50Ω
∴ Thus the inductive reactance and the resistance are respectively 10Ω, and 50Ω
During the nuclear reaction described by
| 235 | W → | 235 | X→ | 231 | Y |
| 92 | 93 | 91 |
the particles emitted are respectively
α and α
α and β
β and β
β and α
Correct answer is D
The decay process illustrated above shows that the lost β -particle to decay to the X by increase its atomic number ( from 92 to 93) and leaving the mass no. unaffected. There after, x decayed by -α emission to give Y, by decreasing the mass no. by 2 ( from 93 to 91).
Thus , the emission is β and α particles respectively
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