Explore topic-wise MCQs in Mechanical Engineering.

This section includes 346 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.

101.

Which command of an LCD is used to shift the entire display to the right?

A. 0x1c
B. 0x18
C. 0x05
D. 0x07
Answer» B. 0x18
102.

Which of the following step/s is/are correct to perform reading operation from an LCD?

A. low to high pulse at e pin
B. r/w pin is set high
C. low to high pulse at e pin & r/w pin is set high
D. none of the mentioned
Answer» D. none of the mentioned
103.

Which pin of the LCD is used for adjusting its contrast?

A. pin no 1
B. pin no 2
C. pin no 3
D. pin no 4
Answer» D. pin no 4
104.

To identify that which key is being pressed, we need to:

A. ground all the pins of the port at a time
B. ground pins of the port one at a time
C. connect all the pins of the port to the main supply at a time
D. none of the mentioned
Answer» C. connect all the pins of the port to the main supply at a time
105.

For writing commands on an LCD, RS bit is

A. set
B. reset
C. set & reset
D. none of the mentioned
Answer» C. set & reset
106.

How many rows and columns are present in a 16*2 alphanumeric LCD?

A. rows=2, columns=32
B. rows=16, columns=2
C. rows=16, columns=16
D. rows=2, columns=16
Answer» E.
107.

Key press detection and Key identification are:

A. the same processes
B. two different works are done in keyboard interfacing
C. none of the mentioned
D. any of the mentioned
Answer» C. none of the mentioned
108.

If we need to operate a key of a keyboard in an interrupt mode, then it will generate what kind of interrupt?

A. es
B. ex0/ex1
C. t0/t1
D. reset
Answer» C. t0/t1
109.

To detect that in which column, the key is placed?

A. we can mask the bits and then check it
B. we can rotate the bits and then check that particular bit which is set or reset(according to the particular condition)
C. none of the mentioned
D. all of the mentioned
Answer» E.
110.

Which of the following steps detects the key in a 4*4 keyboard matrix about the key that is being pressed?

A. masking of bits
B. ensuring that initially, all keys are open
C. checking that whether the key is actually pressed or not
D. all of the mentioned
Answer» E.
111.

In reading the columns of a matrix, if no key is pressed we should get all in binary notation

A. 0
B. 1
C. f
D. 7
Answer» C. f
112.

The pin that clears the control word register of 8255 when enabled is

A. clear
B. set
C. reset
D. clk
Answer» D. clk
113.

If A1=0, A0=1 then the input read cycle is performed from

A. port a to data bus
B. port b to data bus
C. port c to data bus
D. cwr to data bus
Answer» C. port c to data bus
114.

The port that is used for the generation of handshake lines in mode 1 or mode 2 is

A. port a
B. port b
C. port c lower
D. port c upper
Answer» E.
115.

The device that receives or transmits data upon the execution of input or output instructions by the microprocessor is

A. control word register
B. read/write control logic
C. 3-state bidirectional buffer
D. none of the mentioned
Answer» D. none of the mentioned
116.

The input provided by the microprocessor to the read/write control logic is

A. reset
B. a1
C. wr(active low)
D. all of the mentioned
Answer» E.
117.

The data bus buffer is controlled by

A. control word register
B. read/write control logic
C. data bus
D. none of the mentioned
Answer» C. data bus
118.

All the functions of the ports of 8255 are achieved by programming the bits of an internal register called

A. data bus control
B. read logic control
C. control word register
D. none of the mentioned
Answer» D. none of the mentioned
119.

Port C of 8255 can function independently as

A. input port
B. output port
C. either input or output ports
D. both input and output ports
Answer» D. both input and output ports
120.

Programmable peripheral input-output port is another name for

A. serial input-output port
B. parallel input-output port
C. serial input port
D. parallel output port
Answer» C. serial input port
121.

How many bytes of bit addressable memory is present in 8051 based microcontrollers?

A. 8 bytes
B. 32 bytes
C. 16 bytes
D. 128 bytes
Answer» D. 128 bytes
122.

If we push data onto the stack then the stack pointer

A. increases with every push
B. decreases with every push
C. increases & decreases with every push
D. none of the mentioned
Answer» B. decreases with every push
123.

How are the bits of the register PSW affected if we select Bank2 of 8051?

A. psw.5=0 and psw.4=1
B. psw.2=0 and psw.3=1
C. psw.3=1 and psw.4=1
D. psw.3=0 and psw.4=1
Answer» E.
124.

When the microcontroller executes some arithmetic operations, then the flag bits of which register are affected?

A. psw
B. sp
C. dptr
D. pc
Answer» B. sp
125.

When 8051 wakes up then 0x00 is loaded to which register?

A. psw
B. sp
C. pc
D. none of the mentioned
Answer» D. none of the mentioned
126.

8051 series has how many 16 bit registers?

A. 2
B. 3
C. 1
Answer» B. 3
127.

AT89C2051 has RAM of:

A. 128 bytes
B. 256 bytes
C. 64 bytes
D. 512 bytes
Answer» B. 256 bytes
128.

8051 microcontrollers are manufactured by which of the following companies?

A. atmel
B. philips
C. intel
D. all of the mentioned
Answer» E.
129.

The instruction that represents the ‘rotate source, count’ is

A. rcl
B. rcr
C. ror
D. all of the mentioned
Answer» E.
130.

The instruction that multiplies the content of AL with a signed immediate operand is

A. mul
B. smul
C. imul
D. none of the mentioned
Answer» D. none of the mentioned
131.

The statement that is true for the instruction POP*A is

A. flags are unaffected
B. no operands are required
C. exceptions generated are same as that of push*a
D. all of the mentioned
Answer» E.
132.

While executing the PUSH*A instruction, the stack pointer is decremented by

A. 1 bit
B. 2 bits
C. 4 bits
D. 16 bits
Answer» C. 4 bits
133.

The instruction that pushes the general purpose registers, pointer and index registers on to the stack is

A. popf
B. push imd
C. push*a
D. pushf
Answer» D. pushf
134.

The representation of 8-bit or 16-bit signed binary operands using 2’s complement is a data type of

A. ordinal
B. ascii
C. packed bcd
D. integer
Answer» E.
135.

Which of the following is not a data type of 80286?

A. ordinal or unsigned
B. ascii
C. packed bcd
D. none of the mentioned
Answer» E.
136.

The address of a location of the operand is calculated by adding the contents of any of the base registers, with the contents of any of index registers in

A. based indexed mode with displacement
B. based indexed mode
C. based mode
D. indexed mode
Answer» C. based mode
137.

In which of the following addressing mode, the offset is obtained by adding displacement, with the contents of SI?

A. direct mode
B. register mode
C. based mode
D. indexed mode
Answer» E.
138.

In which of the following addressing mode, the offset is obtained by adding displacement and contents of one of the base registers?

A. direct mode
B. register mode
C. based mode
D. indexed mode
Answer» D. indexed mode
139.

In register address mode, the operand is stored in

A. 8-bit general purpose register
B. 16-bit general purpose register
C. si or di
D. all of the mentioned
Answer» E.
140.

In which of these modes, the immediate operand is included in the instruction itself?

A. register operand mode
B. immediate operand mode
C. register and immediate operand mode
D. none of the mentioned
Answer» C. register and immediate operand mode
141.

The device that generates the basic timing clock signal for the operation of the circuit using crystal oscillator is

A. timing unit
B. timing and control unit
C. oscillator
D. clock generator
Answer» D. clock generator
142.

The registers that are not accessible by the user are

A. accumulator and b register
B. ip and ie
C. instruction registers
D. tmp1 and tmp2
Answer» E.
143.

The register that provides control and status information about counters is

A. ip
B. tmod
C. tscon
D. pcon
Answer» C. tscon
144.

The architecture of 8051 consists of

A. 4 latches
B. 2 timer registers
C. 4 on-chip i/o ports
D. all of the mentioned
Answer» E.
145.

The register that provides control and status information about serial port is

A. ip
B. ie
C. tscon
D. pcon and scon
Answer» E.
146.

The receive buffer of serial data buffer is a

A. serial-in parallel-out register
B. parallel-in serial-out register
C. serial-in serial-out register
D. parallel-in parallel-out register
Answer» B. parallel-in serial-out register
147.

The transmit buffer of serial data buffer is a

A. serial-in parallel-out register
B. parallel-in serial-out register
C. serial-in serial-out register
D. parallel-in parallel-out register
Answer» C. serial-in serial-out register
148.

Which of the processor’s stack does not contain the top-down data structure?

A. 8086
B. 80286
C. 8051
D. 80386
Answer» D. 80386
149.

The register that can be used as a scratch pad is

A. accumulator
B. b register
C. data register
D. accumulator and b register
Answer» C. data register
150.

A chemical transduction system is interfaced to the optical fibre at its end. This type of sensor is called?

A. chemical sensor
B. thermal sensor
C. photoelectric sensor
D. light sensor
Answer» B. thermal sensor