Q. The equation of motion for a spring-mass system excited by a harmonic force is where M is the mass, K is the spring stiffness, F is the force amplitude and w is the angular frequency of excitation. Resonance occurs when w is equal to Ans: Option D

Q. A bar of uniform cross section and weighing 100 N is held horizontally using two massless and inextensible strings S1 and S2 as shown in the figure. The tensions in the strings are Ans: T1 = 0 N and T2 = 100 N

Q. Four red balls, four green balls and four blue balls are put in a box. Three balls are pulled out of the box at random one after another without replacement. The probability that all the three balls are red is (A) 1/72                      (B) 1/55                      (C)  ...

Q. A multi-mode optical fiber with a large core diameter has a core refractive index 𝑛1 = 1.5 and cladding refractive index 𝑛2 = 1.4142. The maximum value of 𝜃𝐴 (in degrees) for which the incident light from air will be guided in the optical fiber is ±                  . Ans: 29-31

Q. A Michelson Interferometer using a laser source of wavelength 𝜆0 = 500 nm, with both the mirrors (𝑀1& 𝑀2) fixed and positioned equidistant from the splitter/combiner is shown in the figure. When a dielectric plate of refractive index 𝑛 = 1.5, of thickness 𝒕 , is placed in front of the ...

Q. The sampling rate for Compact Discs (CDs) is 44,000 samples/s. If the samples are quantized to 256 levels and binary coded, the corresponding bit rate (in bits per second) is . Ans: 352000

Q. Assuming ideal opamp, the RMS voltage (in mV) in the output Vo only due to the 230 V, 50 Hz interference is (up to one decimal place) _. Ans: 10.6-11

Q. A 1000 W strain gage (Rg) has a gage factor of 2.5. It is connected in the bridge as shown in figure. The strain gage is subjected with a positive strain of 400 mm/m. The output Vo (in mV) of the bridge is (up to two decimal places) . Ans: 0.48-0.51

Q. The average velocity v of flow of clear water in a 100 cm (inner) diameter tube is measured using the ultrasonic flow meter as shown in the figure. The angle q is 45°. The measured transit times are t1 = 0.9950 ms and t2 = 1.0000 ms. The velocity v (in m/s) in the pipe is (up to one decimal ...

Q. The inductance of a coil is measured using the bridge shown in the figure. Balance (D = 0) is obtained with C1 = 1 nF, R1 = 2.2 MΩ, R2 = 22.2 kΩ, R4 = 10 kΩ. The value of the inductance Lx (in mH) is Ans: 221 - 223