Question:
An opaque cylinder (shown below) is suspended in the path of a parallel beam of light, such that its shadow is cast on a screen oriented perpendicular to the direction of the light beam. The cylinder can be reoriented in any direction within the light beam. Under these conditions, which one of the shadows P, Q, R, and S is NOT possible?
An opaque cylinder (shown below) is suspended in the path of a parallel beam of light, such that its shadow is cast on a screen oriented perpendicular to the direction of the light beam. The cylinder can be reoriented in any direction within the light beam. Under these conditions, which one of the shadows P, Q, R, and S is NOT possible?
Show Hint
- Shadows of cylindrical objects can be circular or elliptical depending on the angle of light.
- Unusual or impossible shadows result from incorrect assumptions about the object's positioning or light angles.
- Unusual or impossible shadows result from incorrect assumptions about the object's positioning or light angles.
Updated On: Aug 30, 2025
- P
- Q
- R
- S
Hide Solution
Verified By Collegedunia
The Correct Option is D
Solution and Explanation
We are given an opaque cylinder suspended in the path of a parallel beam of light, and the task is to analyze which shadow cannot be formed based on the cylinder's reorientation.
1) Shadow Formation:
When a cylindrical object is in the path of light, the shadow produced depends on the orientation of the cylinder.
- When the cylinder is oriented with its axis perpendicular to the direction of the light, it will cast a circular shadow.
- When the cylinder is reoriented with its axis at an angle to the light, the shadow may become elliptical.
- A shadow like \( S \) (which appears highly distorted) is not physically possible as it would require an impossible angle or distortion of light.
2) Conclusion:
The shadow in option \( S \) cannot be produced by the cylinder under the given conditions. Therefore, the correct answer is option (D).
\[ \boxed{\text{The correct answer is (D) S.}} \]
1) Shadow Formation:
When a cylindrical object is in the path of light, the shadow produced depends on the orientation of the cylinder.
- When the cylinder is oriented with its axis perpendicular to the direction of the light, it will cast a circular shadow.
- When the cylinder is reoriented with its axis at an angle to the light, the shadow may become elliptical.
- A shadow like \( S \) (which appears highly distorted) is not physically possible as it would require an impossible angle or distortion of light.
2) Conclusion:
The shadow in option \( S \) cannot be produced by the cylinder under the given conditions. Therefore, the correct answer is option (D).
\[ \boxed{\text{The correct answer is (D) S.}} \]
Was this answer helpful?
0
0
Top Questions on Petroleum Exploration and Drilling Engineering
- In a capillary rise experiment with a capillary tube of length $l_1$, water rises to a height $h$ such that $h<l_1$. If the capillary tube is cut to a length $l_2$ such that $l_2<h$, and the experiment is repeated, which of the following statements is/are CORRECT?
- GATE PE - 2026
- Petroleum Engineering
- Petroleum Exploration and Drilling Engineering
- A vertical well is drilled up to a depth of 4000 ft. Further drilling starts with 10 ppg of fresh mud and 50000 lbf weight on bit (WOB). An equivalent circulation density (ECD) of 10.75 ppg was recorded. The total circulation pressure loss is estimated to be 110 psi. The steel density is 65.5 ppg. The decrease in hook load is _________ lbf (rounded off to one decimal place). (Note: 1 ppg mud is equivalent to 0.052 psi/ft.)
- GATE PE - 2026
- Petroleum Engineering
- Petroleum Exploration and Drilling Engineering
- A kill mud of appropriate density is required to be injected in a well such that the shut-in pressure is $6.8 \times 10^{6}\ \mathrm{Pa}$ at a depth of $3500\ \mathrm{m}$. Here, the shut-in pressure is the quantity by which the bottom-hole pressure exceeds the hydrostatic pressure of the original mud at the given depth. The density of the original mud is $1100\ \mathrm{kg/m^3}$. The density of the kill mud is _________ kg/m$^3$ (rounded to two decimal places).
- GATE PE - 2023
- Petroleum Engineering
- Petroleum Exploration and Drilling Engineering
After well completion, a discovery well in an oil reservoir is produced for a short period and then closed for pressure build-up test. The production history before shut-in is given below. The Horner’s pseudo-producing time, $t_{pH}$, is ............... hr (rounded to nearest integer).
Production rate (STB/day) Duration (days) 500 5 550 7 400 8 - GATE PE - 2023
- Petroleum Engineering
- Petroleum Exploration and Drilling Engineering
A build-up test is characterized by production at constant rate over time $t_p$, followed by shut-in period of $\Delta t$. A plot of shut-in bottom hole pressure ($P_{ws}$) with $\log \left(\dfrac{t_p+\Delta t}{\Delta t}\right)$ for pressure build-up test data is shown in the figure. Which of the following statement(s) is/are TRUE?
- GATE PE - 2023
- Petroleum Engineering
- Petroleum Exploration and Drilling Engineering
View More Questions
Questions Asked in GATE PE exam
- Classification of kerogen is based on the relative amount of Carbon (C), Hydrogen (H) and Oxygen (O). Which ONE of the following options is CORRECT about Type II kerogen?
- GATE PE - 2026
- Geochemistry
- Which of the following option(s) is/are CORRECT for well testing analysis of a reservoir?
- GATE PE - 2026
- Reservoir capacity
- The porosity of a formation with matrix density of 2.65 g/cc and fluid density of 1.0 g/cc is 0.15. The formation has shear modulus of 30 GPa and bulk modulus of 36 GPa. The compressional wave velocity in the formation is _________ $\times 10^3$ m/s (rounded off to two decimal places).
- GATE PE - 2026
- Rock Physics
- The laboratory analysis data obtained from the core is as follows:
Weight of clean dry core in air = 30 g
Weight of core completely saturated with oil = 32 g
Weight of saturated core completely immersed in oil = 24 g
If the density of oil used for saturation of core during the experiment is 0.88 g/cc, then the effective porosity of the core is _________% (rounded off to two decimal places).
- GATE PE - 2026
- Buoyancy and Floatation
- Log-log plot of pressure drop (\( \Delta p \)) versus time (\( t \)) obtained using well test data is matched with one of the Grigarten type curves. Thereafter, a point on the type curve is chosen with \( P_d = 10 \) and \( t_d/C_d = 100 \), where \( P_d, t_d, C_d \) are dimensionless pressure, dimensionless time, and dimensionless wellbore storage, respectively.
The corresponding match point on the log-log plot is \( \Delta p = 250 \) psi and \( t = 10 \) hrs. Oil flow rate is 500 rb/day. Viscosity of oil is 1.5 cP. Thickness of the reservoir is 10 ft and formation volume factor of oil is 1.2 rb/stb.
The permeability of the reservoir is .......... mD (rounded off to one decimal place).
- GATE PE - 2025
- Reservoir and channel routing
View More Questions