A steel frame (K = 45W/m-°C) of total length 60cm and - cross-sectional area 0.20cm2, forms three sides of a square. The free ends are maintained at 20°C and 40°C. Find the rate of heat flow through a cross-section of the frame.
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A 1 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20cm...........?
Focal length f = 20 cm Object distance u = -15 cm Image distance v= ? The lens formula is 1/f = 1/v - 1/u 1/v = 1/u + 1/f 1/v = 1/-15 + 1/20 1/v...
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A load of 10 kg is suspended by a metal wire 3 m long and having a cross-sectional area 4 mm^2. Find
Length of wire L= 3 m, Load F = 10*10 N =100 N, {taking g = 10 m/s²} Area of cross-section A = 4 mm² →A = 4x10⁻⁶ m² (a) The stress = Load...
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A steel wire and a copper wire of equal length and equal cross-sectional area are joined end to end and the combination is subjected to a tension.
(a) Since both types of wires are joined end to end, the same load will be on the cross-sections of them. If the load = F and the area of...
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A steel rod of cross-sectional area 4cm^2 and length 2m shrinks by 0.1cm as the temperature decreases in night.
Length of the rod =L =2 m The length increased during the night = l =0.1 cm= 0.001 m The strain developed during the night =l/L =0.001/2 =0.0005 If the tension developed =...
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A copper wire of cross-sectional area 0.01 cm^2 is under a tension of 20 N. Find the decrease in the cross-sectional area.
Cross-sectional area A =0.01 cm² →A = 0.01/10000 =1x10⁻⁶ m² Stress = 20/1x10⁻⁶ N/m² =2x10⁷ N/m² Hence the longitudinal strain =Stress/Y =2x10⁷/1.1x10¹¹ =1.82x10⁻⁴ Poisson's ratio = 0.32 Lateral strain = 0.32*1.82x10⁻⁴ =5.82x10⁻⁵ Taking the cross-section as...
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A reference frame attached to the earth (a) is an inertial frame by definition
(b) cannot be an inertial frame because the earth is revolving around the sun (d) cannot be an inertial frame because the earth is rotating about its axis. Explanation: A reference frame attached...
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A particle stays at rest as seen in a frame. We can conclude that (a) the frame is inertial
(c) the frame may be inertial but the resultant force on the particle is zero (d) the frame may be noninertial but there is a nonzero resultant force. Explanation: (a) is incorrect because...
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A particle is found to be at rest when seen from a frame S1 and moving with a constant velocity when seen from another frame S2.
(a) Both the frames are inertial. (b) Both the frames are noninertial. Explanation: S1 is moving with constant velocity w.r.t frame S2 . So, if S1 is inertial, then S2 will be inertial...
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Derive the expression for the self inductance of a long solenoid of cross sectional area A and length l, having n turns per unit length.
Magnetic field inside the solenoid B =μ0nI n → number of turns per unit length, I → current flowing, ϕ' = Magnetic field through each turn = BA = μ0nIA Total magnetic flux linked...
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The dielectric strength of air is 3.0 x 10^6V/m. A parallel-plate air-capacitor has area 20cm^2 and plate separation 0.10mm.
E = 3 × 106V/m, A = 20cm2, d = 0.1mm Potential diff. across the capacitor = Ed = 3 × 106 × 0.1 × 10–3 = 300V Max. rms Voltage = V/√2 =...
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