Related Questions

একটি স্টেপ আপ ট্রান্সফরমারে, গৌণ কুণ্ডলীর পাকসংখ্যা মুখ্য কুন্ডলীর পাকসংখ্যার দ্বিগুণ। যদি মূখ্য কুন্ডলীকে কোন পরিবর্তী বিদ্যুৎ লাইনের সাথে সংযুক্ত করা হয়, তাহলে মুখ্য কুণ্ডলীর তুলনায় গৌণ কুণ্ডলীতে- (In a step up transformer, the number of turns in the secondary coil is twice to that of primary coil. If you apply an alternating current in the primary coil, then in the secondary coil compared to the primary coil-)
A তড়িৎ প্রবাহের মান দ্বিগুণ হবে (current will be doubled)
B তড়িৎ প্রবাহের মান অর্ধেক হবে (current will be halved)
C তড়িৎ বিভবের মান অর্ধেক হবে (voltage will be halved)
D তড়িৎ প্রবাহের মান সমান থাকবে (Current will remain the same)
In an iron cored coil the iron core is removed so that the coil becomes an air cored coil. The inductance of the coil will
A Increase
B Decrease
C Remain the same
D Initially increase and then decrease
A certain amount of current flows through a ring shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil?
A Decreases
B Increases
C Remains same
D First increases and then decreases depending on the depth of iron in¬sertion
Doubling the number of turns of wire in an inductor:
A reduces the value of inductance by one-half
B multiplies the value of inductance by two
C multiplies the value of inductance by four
D reduces the value of inductance by one-fourth
E None of the above
A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, the voltage induced across the coil will
A Increase
B Decrease
C Remain constant
D Be excessive
An ohmmeter is connected across an inductor and the pointer indicates zero ohms. The inductor is
A Good
B Open
C Shorted
D Partly shorted
A close coil helical spring of mean diameter D consists of n coils of diameter d. If it carries an axial load W, the energy stored in the spring, is
A $$\frac{{4{\text{W}}{{\text{D}}^2}{\text{n}}}}{{{{\text{d}}^4}{\text{N}}}}$$
B $$\frac{{4{{\text{W}}^2}{\text{Dn}}}}{{{{\text{d}}^4}{\text{N}}}}$$
C $$\frac{{4{{\text{W}}^2}{{\text{D}}^3}{\text{n}}}}{{{{\text{d}}^4}{\text{N}}}}$$
D $$\frac{{4{{\text{W}}^2}{{\text{D}}^3}{{\text{n}}^2}}}{{{{\text{d}}^4}{\text{N}}}}$$
The ratio of coil diameter to wire diameter of a spring is called the spring
A Index
B Deflection
C Form co-efficient
D None of these
When an open coiled helical compression spring is subjected to an axial compressive load, the maximum shear stress induced in the wire is (where D = Mean diameter of the spring coil, d = Diameter of the spring wire, K = Wahl's stress factor and W = Axial compressive load on the spring)
A $$\frac{{{\text{WD}}}}{{\pi {{\text{d}}^3}}} \times {\text{K}}$$
B $$\frac{{2{\text{WD}}}}{{\pi {{\text{d}}^3}}} \times {\text{K}}$$
C $$\frac{{4{\text{WD}}}}{{\pi {{\text{d}}^3}}} \times {\text{K}}$$
D $$\frac{{8{\text{WD}}}}{{\pi {{\text{d}}^3}}} \times {\text{K}}$$
If doubling a number and adding 20 to the result gives the same answer as multiplying the number by 8 and taking away 4 from the product, the number is :
A 2
B 3
C 4
D 6

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