Physics - Online Test
Q1. When ultraviolet light of wavelength 1000 is incident on molybdenum, then the maximum velocity of ejected electron (given: work function of molybdenum = 5.0eV) is
Answer : Option C
Explaination / Solution:
No Explaination.
Q2. A message signal of frequency 10 kHz and peak voltage of 10 volts is used to modulate a carrier of frequency 1 MHz and peak Voltage of 20 volts. Determine the modulation index
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. Vectors can be added by
Answer : Option B
Explaination / Solution:
Parallelogram law of vector addition is,If two vectors are considered to be the adjacent sides of a Parallelogram, then the resultant of two vectors is given by the vector which is a diagonal passing through the point of contact of two vectors.
Q4. A pendulum bob of mass m carrying a charge q is at rest with its string making an angle θ with the vertical in a uniform horizontal electric field E. The tension in the string is
Answer : Option C
Explaination / Solution:
TCos TSin
TCos TSin
Q5. What is the density of water at a depth where pressure is 80.0 atm, given that its density at the surface is 1.03 kg ?
Answer : Option A
Explaination / Solution:
No Explaination.
Q6.
Consider the cyclic process depicted in Figure if is negative for the process CA, what are the signs of Q and W are associated with CA?
Answer : Option B
Explaination / Solution:
Q7. A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is the tension in the string?
Answer : Option A
Explaination / Solution:
Let, m=0.25 kg, r= 1.5m and f= 40 rev/min = 40 rev /60 s= 2/3 rps
Tension in the string = Centripetal force
so,
Q8. In which of the following cases is the work done positive?
Answer : Option C
Explaination / Solution:
When a body is moving on a rough horizontal surface then their will be 2 forces acting on the body
1. Applied force ( in the direction of motion)
2. friction ( opposite to direction of motion)
As applied force is in same direction as displacement so work done will be positive.
Q9. The equivalent resistance of two resistances P and Q which are in series is
Answer : Option C
Explaination / Solution:
Equivalent resistance of two resistances connected in series is equal to the sum of the two resistances.
Q10. A triply ionized beryllium ion , (a beryllium atom with three electrons removed), behaves very much like a hydrogen atom except that the nuclear charge is four times as great. For the hydrogen atom, the wavelength of the photon emitted in the n =2 to n=1 to transition is 122 nm. What is the wavelength of the photon emitted when a ion undergoes this transition?
Answer : Option C
Explaination / Solution:
No Explaination.
