List of top Geophysics Questions

In Newton's Ring experiment with reflected light, the correct vertically downward arrangement of equipments is:
A. Microscope, Glass plate at \(45^\circ\), Plano-convex lens, Plane glass plate.
B. Plano-convex lens, Microscope, Plane glass plate.
C. Glass plate at \(60^\circ\), Microscope, Plano-convex lens.
D. Microscope, Plane glass plate, Plano-convex lens.

Which of the following holds for coherence of light?
A. Coherence is mainly divided into temporal and spatial coherence,
B. Temporal coherence is directly related to finite bandwidth of source,
C. Spatial coherence is related to finite size of the source,
D. Spatial coherence is related to finite bandwidth of the source.

Which of the following is reversible process?

One mole of an ideal gas expands isothermally to ten times its initial volume. The change in entropy in terms of \(R\) is:

In a Michelson interferometer, \(100\) fringes cross the field of view when the movable mirror is moved through \(29.48\ \mu m\). The wavelength of light used is:

The direction in a uniaxial crystal along which the e-ray and o-ray travel with same speed is:

Newton's Rings are formed when a plano-convex lens of large radius of curvature placed on a plane glass plate is illuminated with monochromatic light.

For a wave train of wavelength \(\lambda\) having \(N\) number of wave oscillations, the coherence length is:

Given below are two statements:
Assertion (A): The Fraunhofer diffraction is produced by the interference between parallel rays. The Fraunhofer diffraction can be observed using two convex lenses.
Reason (R): The two convex lenses are used to observe Fraunhofer diffraction, one to make light from the source parallel and other to focus the light after diffraction on to the screen.

Two long coaxial metal cylinders of inner radius \(r_1\) and outer radius \(r_2\) are separated by material of conductivity \(k\). If cylinders are kept at a potential difference of \(V\), the current flows from one to the other in length \(l\) is:

The common emitter configuration of transistor gives:

A Negative feedback:

Calculate ripple factor in the following at \(50\ \text{Hz}\):
A. \(\pi\) section filter having \(C_1=200\ \mu F,\ C_2=100\ \mu F,\ L_1=50\ mH,\ R_L=100\ \Omega\),
B. \(\pi\) section filter having \(C_1=200\ \mu F,\ C_2=200\ \mu F,\ L_1=50\ mH,\ R_L=100\ \Omega\),
C. \(\pi\) section filter having \(C_1=200\ \mu F,\ C_2=200\ \mu F,\ L_1=100\ mH,\ R_L=100\ \Omega\),
D. \(\pi\) section filter having \(C_1=100\ \mu F,\ C_2=400\ \mu F,\ L_1=100\ mH,\ R_L=200\ \Omega\). Choose the correct answer from the options given below:

Which of the following are correct form of Maxwell's equation?
A. \(\vec{\nabla}\cdot\vec{B}=0\),
B. \(\vec{\nabla}\cdot\vec{E}=\dfrac{\rho}{\epsilon_0}\),
C. \(\vec{\nabla}\times\vec{E}=-\dfrac{\partial \vec{B}}{\partial t}\),
D. \(\dfrac{1}{2}\left(\epsilon_0E^2+\dfrac{B^2}{\mu_0}\right)=U\). Choose the correct answer from the options given below:

Given below are two statements:
Assertion (A): FETs are in general more suitable than BJTs particularly at low frequencies.
Reason (R): The reason of more suitability of FETs than BJTs at low frequencies is their high input resistance and high power gain.

Poynting Vector:

Which of the following is invariant under Galilean Transformation?
A. Velocity,
B. Linear Momentum,
C. Acceleration,
D. Length, E. Force. Choose the correct answer from the options given below:

Which of the following is true in a series LCR circuit, at \(X_L=X_C\)?
A. Total impedance is equal to resistance \(R\),
B. Current in circuit is in phase with applied emf,
C. Current in circuit leads the emf by \(\dfrac{\pi}{2}\),
D. Current in circuit lags the emf by \(\dfrac{\pi}{2}\), E. Current may lead or lag the emf by \(\dfrac{\pi}{4}\). Choose the correct answer from the options given below:

Which of the following represent correct form of displacement current?

Given below are two statements:
Assertion (A): The laws of Physics all take the same identical form for all frames of reference in uniform relative motion, for all inertial frame of references.
Reason (R): This is due to absence of an absolute or fixed frame of reference.

A rocket motor consumes \(3000\ \text{kg}\) of fuel per minute exhausting it with a speed of \(5\times10^3\ \text{m/s}\). The magnitude of force exerted on rocket is:

Two projectiles are subject to the same acceleration. Motion of one projectile as seen from another projectile will always be a:

Calculate the effective weight of astronaut of ordinarily weighing \(w\ \text{kg}\), when his rocket moves with acceleration \(a'\ \text{m/s}^2\) in the following cases:
A. \(w=60\ \text{kg}, a=5g\) upwards,
B. \(w=60\ \text{kg}, a=8g\) upwards,
C. \(w=50\ \text{kg}, a=6g\) upwards,
D. \(w=60\ \text{kg}, a=10g\) upwards. Choose the correct answer from the options given below:

In parallel resonance circuit, the current:

The velocity of sound in a gas in which waves of wavelength \(1\ \text{m}\) and \(1.01\ \text{m}\) produces \(10\) beats per second is: