A photon of wavelength 6.0 x 10\(^{-7}\) m behaves like a particle of a certain mass. The value of that mass is [h = 6.63 x 10\(^{-34}\) Js, c = 3.0 x 10\(^8\) ms\(^{-1}\)]
- A. 3.5 x 10\(^{-36}\)kg
- B. 2.2 x 10\(^{-35}\)kg
- C. 1.1 x 10\(^{-35}\)kg
- D. 2.2 x 10\(^{-7}\) kg
A radioactive substance has a half life of 20 days. What fraction of the original radioactive nuclei will remain after 80 days?
- A. \( \frac{1}{32} \)
- B. \( \frac{1}{16} \)
- C. \( \frac{1}{8} \)
- D. \( \frac{1}{4} \)
A 120V, 60W lamp is to be operated on 220V ac supply mains. calculate the value of non inductive resistance that would be required to ensure that the lamp is run on correct value
- A. 100Ω
- B. 200Ω
- C. 300Ω
- D. 500Ω
Lenz’s law is a law of conservation of
- A. electric charge
- B. electric current
- C. Energy
- D. Momentum
Two long parallel wires X and Y carry currents 3A and 5A each. if the force experienced by unit length is 5 x 10-5N. the force per unit length experienced by wire Y is
- A. 3 x 10-5
- B. 3 x 10-6
- C. 5 x 105
- D. 5 x 10-5
The instrument that measures both ac and dc is called
- A. A current balance
- B. a moving coil ammenter
- C. a moving iron ammeter
- D. an inverter
A 40KW electric cable was used to transmit electricity through a resistor of resistance 2.00Ω at 800V. The power loss as internal energy is
- A. 4.0 x 102W
- B. 5.0 x 102W
- C. 4.0 x 103W
- D. 5.0 x 103W
A conductor has a diameter of 1.00mm and length of 2.00m. If the resistance of the material is 0.1Ω, the resistivity is
- A. 2.55 * 105 Ωm
- B. 2.55 * 103 Ωm
- C. 3.93 * 10-6 Ωm
- D. 3.93 * 10-8 Ωm
If two charged plates are maintained at a potential difference of 3 kv, the work done in taking a charge of 600µc across the field is
- A. 0.8j
- B. 1.8j
- C. 9.0j
- D. 18.0j
The difference observed in solids, liquids and gases can be accounted for by
- A. The different molecules in each of them
- B. The spaces and forces acting between the molecules
- C. Thier melting points
- D. Their relative massess
Which of the following gas laws is equivalent to the work done?
- A. Boyle' law
- B. Charles law
- C. Pressure law
- D. van der Waal's law
A string of length 4m is extended by 0.02m when a load of 0.4kg is suspended at its end. What will be the length of the string when the applied force is 15N?
- A. 4.05m
- B. 4.08m
- C. 5.05m
- D. 6.08m
A particle of weight 120N is placed on a plane inclined at 300 to the horizontal. If the plane has an efficiency of 60% to the floor what is the force required to push the weight uniformly up the plane?
- A. 50N
- B. 100N
- C. 175N
- D. 210N
118.8cm2 surface of the copper cathode of a voltameter is to be coated with 10-6m thick copper of density 9 x 103kgm-3. How long will the process run with 10A constant current?
[3.3 x 10-7kgC-1]
- A. 5.4 min
- B. 10.8 min
- C. 15.0 min
- D. 20.0 min
from the diagram above, the inductive reactance and the resistance R are respectively
- A. 50Ω and 45Ω
- B. 25Ω and 51Ω
- C. 20Ω and 50Ω
- D. 10Ω and 50Ω
During the nuclear reaction described by
| 235 | W → | 235 | X→ | 231 | Y |
| 92 | 93 | 91 |
the particles emitted are respectively
- A. α and α
- B. α and β
- C. β and β
- D. β and α
The instantaneous value of the induced e.m.f as a function of time is ε = εo sin ωt where εo is the peak value of the e.m.f. The instantaneous value of the e.m.f., one quarter of the period is
- A. 0.00
- B. εo/4
- C. εo/2
- D. εo
In the diagram above , if the magnetic field points into the paper and the force on a current – carrying conductor points upwards, what is the direction of the current?
- A. Upwards
- B. Downwards
- C. Right
- D. Left
Three cells each of e.m.f 1.5 V and internal resistance 2.5Ω are connected as shown in the diagram above. Find the net e.m.f and the internal resistance
- A. 1.5V, 7.50Ω
- B. 1,5V, 0.83Ω
- C. 4.5V, 7.50Ω
- D. 4.5V, 0.83Ω
The fundamental frequency of a plucked wire under a tension of 400N is 250Hz. When the frequency is changed to 500 Hz at constant length, the tension is
- A. 1600N
- B. 400N
- C. 160N
- D. 40N
The ratio of the coefficient of linear expansion of two metals ∝1/∝2 is 3:4. If, when heated through the same temperature change, the ratio of the increase in length of the two metals, e1/e2 is 1:2, the ratio of the original lengths l1/l2 is
- A. 8/3
- B. 3/2
- C. 2/3
- D. 3/8