वक्र सतह से अपवर्तन Refraction at Curve Surface | किरण प्रकाशिकी Ch 9 Lec 4 | 12th Physics Vipin Sir

The radius and height of a right circular cone are in ratio 3 : 4. If its curved surface area (in cm^2 ) is 240 pi , then its volume (in cm^3 ) is: एक गोलाकार शंकु की त्रिज्या और ऊंचाई अनुपात 3: 4 में है। यदि इसकी वक्र सतह का क्षेत्रफल ( cm^2 में) 240% है, तो इसकी आयतन ( cm^3 में) है?

A bi-convex lens is formed with two thin plano-convex lenses as shown in the figure. Refractive index n of th efirst lens is 1.5 and that of the second lens if 1.2 Both the curved surfaces are of the same radius of curvature R=14cm. For this bi-convex lens, for an object distance of 40cm, the image distance will be

Find the curved surface area of frustum of a cone of height 12 cm and radii of circular ends are 9 cm and 4 cm.

What will be total cost of polishing curved surface of a wooden cylinder at rate of Rs 20 per m^2 if its diameter is 40 cm and height is 7m? लकड़ी की बेलन की वक्र सतह को 20 रुपये प्रति वर्ग मीटर की दर से पॉलिश करने की कुल लागत क्‍या होगी, यदि इसका व्यास 40 सेमी तथा ऊंचाई 7 मीटर है |

State Whether TRUE or FALSE: If c,t and v are curved surface area, total surface area and volume of a cylinder then show that th^(2)=ch^(2)+4v^(2)=8v^(2)rh Where r and h are radius and height.

A thin oil film of refracting index 1.2 floats on the surface of water (mu=4/3) . When a light of wavelength lamda=9.6xx10^(-7)m falls normally on the film air, then it appears dark when seen normally. The minimum change in its thickness for which it will appear bright in normally reflected light by the same light is Zxx10^(-7)m . Then find Z .

The ratio of curved surface area and volume of a cylinder is 1: 7. The ratio of total surface area and volume is 187 : 770. What is the respective ratio of its base radius and height? एक बेलन के वक्र पृष्ठीय क्षेत्रफल तथा आयतन का अनुपात 1 : 7 है। कूल पृष्ठोय क्षेत्रफल तथा आयतन का अनुपात 187 : 770 है। इसके आधार की त्रिज्या तथा ऊँचाई क्रमशः अनुपात क्या है? Option 1- 5 : 8 Option 2- 4 : 9 Option 3- 3 : 7 Option 4- 7 : 10

A beaker of radius r is filled with water (refractive index (4)/(3) ) up to a height H as shown in the figure on the left. The beaker is kept on a horizontal table rotating with angular speed omega . This makes the water surface curved so that the difference in the height of water level at the centre and the circumference of the beaker is h (h lt lt H, h lt lt r) as shown in the figure on the right . Take this surface to be approximately spherical with a radius of curvalture R . Which of the following is/are correct ? (g is acceleration due to gravity)

The average of twelve numbers is 55.5. The average of the first four numbers is 53.4 and that of the next four numbers is 54.6. The 10th number is greater than the 9th number by 3 but lesser than the 11th and 12th numbers by 2 and 3, respectively. What is the average of the 10th and the 12th numbers? बारह संख्याओं का औसत 55.5 है | पहली चार संख्याओं का औसत 53.4 है तथा अगली चार संख्याओं का औसत 54.6 है | 10वीं संख्या 9वीं संख्या से 3 अधिक है लेकिन 11वीं और 12वीं संख्याओं से क्रमशः 2 और 3 कम है | 10वीं और 12वीं संख्याओं का औसत ज्ञात करें |

A metallic hemispherical bowl is made up of steel. The total steel used in making the bowl is 342 pi cm^3, The bowl can hold 144 pi cm^3 water. What is the thickness (in cm) of bowl and the curved surface area (in cm^2 ) of outer side? इस्पात से धातु का एक अर्धगोलाकार कटोरा बनाया गया है। कटोरे को बनाने में कुल 342 pi से.मी.^3 इस्पात का प्रयोग किया गया है। कटोरा में 144 pi से.मी.^3 जल आ सकता है। कटोरे की मोटाई (से,मी. में) तथा बाहरी सतह का वक्र पृष्ठिय क्षेत्रफल ( से.मी.^2 में) क्या हें?