CBSE 12TH PHYSICS - Online Test
Q1. Eddy Currents are
Answer : Option D
Explaination / Solution:
Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. By lenz's law an eddy current creates a magnetic field that opposes a change in the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field.
Q2. Photon has a charge of
Answer : Option A
Explaination / Solution:
Photon has no charge. Photon is the packets of energy.
Q3. Transmitter is a device that
Answer : Option D
Explaination / Solution:
A transmitter is a set up that transmits the message to the receiving end through a communication channel.its main function is to modify the message signal in a form suitable for transmission over the channel and to transmit it.The transmitter is able to generate a radio frequency alternating current that is then applied to the antenna, which, in turn, radiates this as radio waves. There are many types of transmitters depending on the standard being used and the type of device; for example, many modern devices that have communication capabilities have transmitters such as Wi-Fi, Bluetooth, NFC and cellular.
Q4. According to superposition of electric fields
Answer : Option B
Explaination / Solution:
When several electric fields are working on single charge then the total electric field intensity on that charge is given by the vector sum of all electric field intensities
Q5. Which of these statements about Bohr model is correct?
Answer : Option D
Explaination / Solution:
No Explaination.
Q6. The sharpness of resonance is given by
Answer : Option B
Explaination / Solution:
Sharpness of resonance is quantitatively described by a dimensionless number known as Q-factor or quality factor which is numerically equal to ratio of resonant frequency to bandwidth.
therefore
Q-factor = resonant frequency / bandwidth
sharpness of resonance =
Q7. Which of the following is true about equipotential lines
Answer : Option B
Explaination / Solution:
The potential at all points on an equipotential surface is constant and work done in moving a charge on an equipotential surface is zero. Electric field lines show the direction of the electric field at the point. If the electric field lines were tangential, parallel or opposite to the equipotential surface, a tangential field will exist on the surface and work done in moving a charge on the surface is not zero. Therefore electric field lines are always perpendicular to the equipotential surface.
Q8. Domestic power supply in India is
Answer : Option B
Explaination / Solution:
No Explaination.
Q9.
the binding energy of the nucleus is related to mass defect Δm by
Answer : Option D
Explaination / Solution:
This follows from the mass energy equivalence relation of the special theory of relativity, proposed by Einstein.
Q10. For two parallel wires carrying currents Ia and Ib seperated by a distance d, the magnitude of force acting on length L of any of the wires is
Answer : Option B
Explaination / Solution:
The conductor carrying current Ib is placed in the magnetic field created by the conductor carrying current . The force it experiences
