Can anyone help me with these 2 questions please.
Firstly:
The primary coil of a step-up transformer is connected to a source of alternating pd.
The secondary coil is connected to a lamp.
Which line, A to D, in the table correctly describes the flux linkage and current through
the secondary coil in relation to the primary coil?
secondary magnetic flux linkage ....................secondary current
--------------------------------------........................----------------------
primary magnetic flux linkage............................primary current
A..........>1.....................................................................<1
B..........<1.....................................................................<1
C..........>1.....................................................................>1
D..........<1.....................................................................>1
The answer is A and I know why the first column is greater than one, but why is the current ratio less than 1?
The second question is:
A coil of 50 turns has a cross-sectional area of 4.2 × 10–3m2. It is placed at an angle to
a uniform magnetic field of flux density 2.8 × 10–2T, as shown in the diagram, so that
angle ? =50degrees.
What is the change in flux linkage when the coil is rotated anticlockwise until ? =0degrees?
A The flux linkage decreases by 2.1 × 10–3 Wb turns.
B The flux linkage increases by 2.1 × 10–3 Wb turns.
C The flux linkage decreases by 3.8 × 10–3 Wb turns.
D The flux linkage increases by 3.8 × 10–3 Wb turns.
I used BAN cos theta but am not getting the correct answer which is B. Can someone take me through it if possible. Thanks in advance.