Physics - Online Test
Q1. Air at 20.0 in the cylinder of a diesel engine is compressed from an initial pressure of 1.00 atm and volume of 800.0 to a volume of 60.0 . Assume that air behaves as an ideal gas with and that the compression is adiabatic. Find the final temperature of the air
Answer : Option C
Explaination / Solution:
T1V1γ−1=T2V2γ−1T2=T1(V1V2)γ−1=1×(80060)1.4−1=826K
Q2. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black paper
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. The percentage of the original quantity of a radioactive material left after five half lives is approximately
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. The triple points of neon is 24.57 K. Express this temperatures on the Celsius and Fahrenheit scales
Answer : Option B
Explaination / Solution:
TK = 24.57K
after solving
TC = –248.58 C
TF = – 415.44 F
Q5. Which of the following is the most precise device for measuring length?
Answer : Option A
Explaination / Solution:
A device with minimum count is the most suitable to measure length.
Least count of vernier callipers = 1 standard division (SD) – 1 vernier division (VD) = cm
Least count of screw gauge = = = 0.001cm
Least count of an optical device = Wavelength of light 10–5 cm = 0.00001 cm
Hence, it can be inferred that an optical instrument is the most suitable device to measure length.
Q6. Mr Iyer takes a grinder rated 220 V 50 Hz to the U.S where supply is 110 60 Hz . He needs to use a
Answer : Option A
Explaination / Solution:
, hence it is a step up transformer.
Q7. Mobility is defined as
Answer : Option D
Explaination / Solution:
Mobility is defined as the drift velocity acquired by the charge per unit electric field strength. Faster the particle moves in a given electric field strength greater is the mobility.
Q8. Two pendulums of length I meter and 16 meters start vibrating one behind the other from the same stand. At some instant the two are in the mean position in the same phase. The time period of shorter pendulum is T. The minimum time after which the two threads of the pendulums will be one behind the other is
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is B. It is then bent into a circular loop of n turns. The magnetic field at the centre of the coil will be
Answer : Option C
Explaination / Solution:
If the length of the wire is L and the radii of the coils in two cases be and . Then,
Q10. A viewing screen is separated from a double-slit source by 1.2 m. The distance between the two slits is 0.030 mm. The second-order bright fringe m =2 is 4.5 cm from the center line. Wavelength of the light is
Answer : Option A
Explaination / Solution:
No Explaination.
