Ohm's Law Multiple choice Question (Electrical Mcqs) and Answer Part 2

Electrical Engineering Objective Question and Answer 

21- Three equal resistors connected in series  across a source of emf together dissipate 10 watts of power, what should be the power dissipated in the same resistors , when they are connected in parallel across the same source of emf ?

        (A) 10 Watts

        (B) 30 Watts

        (C) 90 Watts

        (D) 270 watts

       Answer: (C)

    22- Current I in the figure is   

        (A) 1.5 A

        (B) 0.5 A

        (C) 3.5 A

        (D) 2.5 A

       Answer: (A)

     23- Four identical resistors are first connected in parallel and then in series.The resultant resistant of first combination to the second will be   

        (A) 1/16 times  

        (B) 1/4 times 

        (C) 4 times  

        (D) 16 times  

       Answer: (A)

      24- Twelve wire of same length and same cross sections are connected in the from of cube as shown in figure below. if the resistance of each wire is R, then the effective resistance between P and Q will be   

        (A) R

        (B) 5/6 R

        (C) 3/4 R

        (D) 4/3 R

       Answer: (B)

      25- When P= power , V = voltage and I= current  , R= resistances and G = conductance , which of the following relation is incorrect? 

        (A) V =√ PR 

        (B) P= V^2 G 

        (C) G=P/I^2

        (D) I=√P/R

       Answer: (C)

        26- The unit of electrical Conductivity is  

        (A) mho/meter

        (B) mho/sq.m 

        (C) ohm/meter

        (D) ohm/sq.m

       Answer: (A)

       27- Which of the following bulbs will have the least resistances ?

        (A) 200 V, 60 W

        (B) 220 V , 100 W

        (C) 115 V, 60 W

        (D) 115 V , 100 W

       Answer: (B)

       28- The ratio of resistances of a 100 W, 220 V lamp to that of a 100 W, 100 V lamp will be nearly  

        (A) 4

        (B) 2 

        (C) 1/2

        (D) 1/4

       Answer: (A)

        29- The resistance of a 100 W , 200 V lamp is 

        (A) 100 ohm 

        (B) 200 ohm 

        (C) 400 ohm

        (D) 1600 ohm

       Answer: (C)

        30- Two i kilo ohm , 1/2 W resistors are connected in series. their combined Resistance value and Wattage will be  

        (A) 2 k ohm , 1/ 2 W

        (B) 2 K ohm, 1 w

        (C) 2 k ohm, 2 W

        (D) 1 k ohm, 1/2 W

       Answer: (B)

         31- Which method can not be used for absolute measurement of resistance  

        (A) Ohm's law method  

        (B) Wheatstone bridge method  

        (C) Releigh Method 

        (D) Lorentz method 

       Answer: (B)

        32- Three 3 ohm resistors are connected to form a triangle, what is the resistance between any two of the corners? 

        (A)  3/4 Ohms

        (B)  3 ohms

        (C) 2 Ohms

        (D) 4/3 Ohms

       Answer: (C)

       33- Five resistances are connected to form a triangle, what is the resistance between any two of the corners ?  

      

        (A) 3/4 Ohms 

        (B) 3 Ohms 

        (C) 2 Ohms 

        (D) 4/3 Ohms 

       Answer: (D)

        34- how many different combinations can be obtained with three resistors, each having the resistance R ? 

        (A) 3

        (B) 4

        (C) 5

        (D) 6

       Answer: (B)

        35- A wire of 0.14 mm diameter and specific resistance 9.6 micro ohm-cm is 440 cm long. The resistance of the wire will be  

        (A) 9.6 ohm

        (B) 11.3 ohm

        (C) 13.7 ohm

        (D)  27.4 ohm

       Answer: (D)

        36- Ohm law is not applicable to   

        (A) dc circuits 

        (B)  high currents 

        (C) small resistors 

        (D)  semi-conductors 

       Answer: (D)

      37- A metal resistor has a resistance of 10 ohm at 0°C, the temperature coefficient  is  

        (A) 0.00625/°C

        (B) 0.0625/°C

        (C) 0.000625/°C

        (D)  0.625/°C

       Answer: (C)

       Five resistances are connected as shown and the combination is connected to a 40 V supply.

       

       38- Voltage between P and Q will be   

        (A) 40 V

        (B) 22.5 V

        (C) 20 V

        (D)  17.5 V

       Answer: (B)

        39- The current in 5 Ohm resistor will be 

        (A) 2.1 A

        (B) 2.7 A

        (C) 3 A

        (D)  3.5 A

       Answer: (D)

        40- Least current will flow through 

        (A) 25 ohm resistor  

        (B) 18 ohm resistor 

        (C) 10 ohm resistor 

        (D)  5 ohm resistor 

       Answer: (A)