Physics - Online Test
Q1. For a parallel ideal LC circuit at resonance the input impedance across L or C is______
Answer : Option D
Explaination / Solution:
in parallel LC circuit, Impedance
at resonance
hence impedance will be infinite.
Q2. At the surface of a charged conductor, electrostatic field must be
Answer : Option A
Explaination / Solution:
Under static conditions, no current exists on the surface of a conductor. If the electric field at its surface is tangential or parallel to the surface, the tangential electric field would cause the charges to move on the surface of the conductor causing currents to flow on its surface. Therefore electrostatic field is always normal to the surface of a charged conductor at every point.
Q3. The radius of gyration of a body about an axis may be defined as the
Answer : Option D
Explaination / Solution:
It is the perpendicular distance from the axis of rotation to a point mass of mass m that gives an equivalent inertia to the original object (of mass, m)
if radius of gyration is k then
Q4. If a ball is spinning in an airflow it develops pressure difference between the lower and upper faces due differences in the
Answer : Option A
Explaination / Solution:
The Magnus effect is an observable phenomenon that is commonly associated with a spinning object that drags air faster around one side, creating a difference in pressure that moves it in the direction of the lower-pressure side.
The Magnus effect often occurs when a spinning sphere (or cylinder) curves away from its principal flight path.
This phenomenon is important in the study of the physics of many ball sports. It is also an important factor in the study of the effects of spinning on guided missiles—and has some engineering uses, for instance in the design of rotor ships and Flettner aeroplanes.
Q5. The molar specific heat at constant volume, for diatomic gases is
Answer : Option C
Explaination / Solution:
for diatomic gases f = 5
Q6. If several thin lenses of focal length … are in contact, the effective focal length is
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. In the mass number range A = 30 to 170, the binding energy per nucleon is
Answer : Option D
Explaination / Solution:
Binding energy per nucleon vs atomic mass curve
Q8. Thermal stress is stress induced in solids
Answer : Option D
Explaination / Solution:
If temperature deformation is permitted to occur freely, no load or stress will beinduced in the structure. In some cases where temperature deformation is not permitted, an internal stress is created. The internal stress created is termed as thermal stress .
Q9. A rectangular current-carrying coil having n turns,area A and a current I flowing, in a uniform magnetic field B experiences a maximum ,torque equal to
Answer : Option A
Explaination / Solution:
The torque experienced by a current carrying conductor placed in a magnetic field is given by .This has a maximum value when;
Q10. When two quantities are multiplied or divided, the relative error in the result is
Answer : Option A
Explaination / Solution:
When two quantities are multiplied or divided, the relative error in the result is the sum of the relative errors in the multipliers.
e.g x=a x b
maximum possible error is:
similarly, for error in quotient: x=
maximum possible error is:
