What is the effective resistance (in Ω) of two resistors 20 Ω and 30 Ω connected in parallel?

What is the effective resistance (in Ω) of two resistors 12 Ω and 24 Ω connected in parallel?

A

36

B

8

C

16

D

72

Two monochromatic waves having frequencies $$\omega $$ and $$\omega + \Delta \omega \left( {\Delta \omega \ll \omega } \right)$$ and corresponding wavelengths $$\lambda $$ and $$\lambda - \Delta \lambda \left( {\Delta \lambda \ll \lambda } \right)$$ of same polarization, travelling along X-axis are superimposed on each other. The phase velocity and group velocity of the resultant wave are respectively given by

A

$$\frac{{\omega \lambda }}{{2\pi }},\,\frac{{\Delta \omega {\lambda ^2}}}{{2\pi \Delta \lambda }}$$

B

$$\omega \lambda ,\,\frac{{\Delta \omega {\lambda ^2}}}{{\Delta \lambda }}$$

C

$$\frac{{\omega \Delta \lambda }}{{2\pi }},\,\frac{{\Delta \omega \Delta \lambda }}{{2\pi }}$$

D

$$\omega \Delta \lambda ,\,\omega \Delta \lambda $$

At a 33kV 50 Hz to a bus a load of 35 MW is connected. To improve the power factor to unity a synchronous phase modifier is connected taking 5 MW. If the SPM is represented as delta connected impedance, where in each phase we have capacitor connected parallel to resistance forming RC parallel network, then the value of this resistance is ___________

A

653.4 Ω

B

753.6 Ω

C

280.4 Ω

D

682 Ω

Two 30 Ω resistors are connected in parallel. What resistance should be connected in series with this parallel combination so that the power in each 30 Ω resistor is one fourth of the total power? Indicate your choice of correct answer.

A

30 Ω

B

15 Ω

C

10 Ω

D

120 Ω

Two resistances of equal value, when connected in parallel, give an equivalent resistance of R. If these resistors are connected in series, the equivalent resistance will be

A

R

B

4R

C

2R

D

R/2

If n resistors of unequal resistances are connected in parallel,and the percenrage error in all resistors are k then,total error in parallel combination is?

A

$x \frac{∂z}{∂x}+y \frac{∂z}{∂y}=\frac{x^2+y^2}{x+y} e^{\frac{x^2+y^2}{x+y}}$

B

$x \frac{∂z}{∂x}+y \frac{∂z}{∂y}=1-\frac{x^2+y^2}{x+y} e^{\frac{x^2+y^2}{x+y}}$

C

$x \frac{∂z}{∂x}+y \frac{∂z}{∂y}=1+\frac{x^2+y^2}{x+y} e^{\frac{x^2+y^2}{x+y}}$

D

$x \frac{∂z}{∂x}+y \frac{∂z}{∂y}=-\frac{x^2+y^2}{x+y} e^{\frac{x^2+y^2}{x+y}}$

Two centrifugal pumps P and R are available for use in a pipe flow system and their head-discharge characteristics are as follows. Pump P Pump R Discharge (cumecs) Head (m) Discharge (cumecs) Head (m) 0 40 0 45 0.12 35 0.14 40 0.2 28 0.24 35 0.3 18 0.3 28 The following statements (S1, S2, and S3) pertain to the head and discharge values during actual operation. Neglect losses in the system. Which of the following statements are correct? S1: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 35 m. S2: When the two pumps P and R are connected in parallel, the discharge is 0.36 cumecs corresponding to a head of 70 m. S3: When the two pumps P and R are connected in series, the discharge is 0.3 cumecs corresponding to a head of 46 m.

A

S2 only

B

S1 and S3

C

S1 and S2

D

S2 and S3

Three 10 kΩ resistors are connected in series. A 20 kΩ resistor is connected in parallel across one of the 10 kΩ resistors. The voltage source is 24 V. The total current in the circuit is

A

900 μA

B

9 mA

C

90 mA

D

800 μA

At a 33kV 50 Hz to a bus a load of 35 MW is connected. To improve the power factor to unity a synchronous phase modifier is connected taking 5 MW. If the SPM is represented as delta connected impedance, where in each phase we have capacitor connected parallel to resistance forming RC parallel network, then the value of this capacitance is __________

A

25.57 μF

B

76.2 μF

C

32.2 μF

D

24 μF

একটি ট্রান্সফরমারের প্রাইমারি ও সেকেন্ডারি তারের ঘূর্ণনের অনুপাত 20ঃ 1 এবং সেকেন্ডারিতে 20 omega রোধ লাগানো আছে। যদি প্রাইমারিতে 220 V প্রয়োগ করা হয় তাহলে এর মধ্যে বিদ্যুৎ প্রবাহ হবে-

A

0.55 A

B

27.5 mA

C

27.5 A

D

5.5 mA

What is the effective resistance (in Ω) of two resistors 20 Ω and 30 Ω connected in parallel?

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