【单选题】
煤矿井下空气中氧气的浓度大于___时，才会引起瓦斯爆炸。
A. 8%#
B. 10%#
C. 12%#
D. 18%
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相关试题
【单选题】
变压器工作时，原、副边电流的关系是___。
A. 同相#
B. 反相#
C. 相差90°#
D. 相差180°
【单选题】
在共发射极电路中，要使三极管具有放大作用，其外部条件是___。
A. 发射结正偏，集电结反偏#
B. 发射结反偏，集电结正偏#
C. 两个结均为正偏#
D. 两个结均为反偏
【单选题】
晶体三极管的输入特性类似于晶体二极管的___。
A. 反向特性#
B. 正向特性#
C. 击穿特性#
D. 截止特性
【单选题】
放大器接入负载后，电压放大倍数会___。
A. 增大#
B. 减小#
C. 不变#
D. 不确定
【单选题】
交流放大电路中的能量来源于___。
A. 输入信号#
B. 三极管的放大作用#
C. 集电极电源#
D. 发射极电源
【单选题】
振荡器中振幅的稳定是由于___。
A. 电源电压限制了振幅#
B. 当振幅达到一定值后正反馈自动停止#
C. 晶体三极管的非线性#
D. 晶体二极管的线性
【单选题】
依靠触发电压的大小来实现翻转的触发器是___。
A. 集基耦合双稳态#
B. 射极耦合双稳态#
C. 单稳态#
D. 多稳态
【单选题】
在电感元件与电容器串联电路中，UL=10V 、UC=5V， 则总电压U=___V。
A. 5#
B. 10#
C. 15#
D. 20
【单选题】
二极管的“或”门电路中只要有一个输入端为高电位，则输出端为___电位。
【单选题】
晶体二极管反向电阻比较___。
A. 小#
B. 大#
C. 极小#
D. 不一定
【单选题】
三极管饱和导通时管压降约为___。
A. 0.7V#
B. 0.3V#
C. 1.4V#
D. 2V
【单选题】
电容器的___不能突变。
A. 感抗#
B. 电流#
C. 容抗#
D. 两端电压
【单选题】
我国规定的允许通过人体的电流值为___。
A. 20mA.s#
B. 30mA.s#
C. 36mA.s#
D. 38mA.s
【单选题】
当我们需要用到多个文件时，通常可以通过___来指定。
A. 文件名#
B. 通配符#
C. 文件夹#
D. 磁盘盘符
【单选题】
在目前的基带传输的矿井监控系统中，基带信号是___的型式。
A. 矩形脉冲#
B. 梯形脉冲#
C. 尖形脉冲#
D. 正弦波
【单选题】
传输线电感的大小与___成反比。
A. 交流电频率#
B. 线间距离#
C. 导线的导磁系数#
D. 导线直径
【单选题】
在"资源管理器"中，如果我们错误地删除了一个文件，可以通过___将其恢复。
A. 剪切按钮#
B. 撤消按钮#
C. 粘贴按钮#
D. 复制按钮
【单选题】
电容器储藏的电场能量与电压的平方成___。
A. 正比
B. 反比#
C. 没关系#
D. 指数
【单选题】
集成电路中常采用的级间耦合方式是___。
A. 直接耦合#
B. 阻容耦合#
C. 变压器耦合#
D. 磁场耦合
【单选题】
将十进制数（3.5）10转换成二进制数是___。
A. 11.11#
B. 10.11#
C. 11.10#
D. 11.01
【单选题】
当我们在电路中引入电压并联负反馈后，与基本放大器的输入、输出电阻相比，反馈放大器的输入、输出电阻的变化是___。 "
A. 输入电阻增大，输出电阻增大#
B. 输出电阻增大，输入电阻减小
C. 输入电阻减小，输出电阻增大#
D. 输入电阻减小或增大，输出电阻不变"
【单选题】
下列对场效应管的描述中，不正确的是___。
A. 场效应管具有输入电阻高，热稳定性好等优点#
B. 场效应管的两种主要类型是MOSFET和JFET#
C. 场效应管可应用于放大#
D. 场效应管可以构成共源、共栅、共漏这几种基本类型的放大
【单选题】
当稳压管在正常稳压工作时，其两端施加的外部电压的特点为___。
A. 反向偏置但不击穿#
B. 正向偏置但不击穿#
C. 反向偏置且被击穿#
D. 正向偏置且被击穿
【单选题】
在杂质半导体中，多数载流子的浓度主要取决于___。
A. 温度#
B. 杂质浓度#
C. 掺杂工艺的类型#
D. 湿度
【单选题】
在输入信号从极小到极大的一次变化过程中，迟滞比较器的输出会发生___次翻转。
【单选题】
在放大器中引入不同反馈可以改变放大器的不同性能。当我们希望达到稳定输出电流时应该引入___。
A. 电压正反馈#
B. 电压负反馈#
C. 电流负反馈#
D. 电流正反馈
【单选题】
三极管放大电路中，静态工作点的合理设置影响到电路能否正常工作及性能如何。共射电路中，若静态工作点设置过低，在输入信号增大时放大器会首先产生___。
A. 交越失真#
B. 放大失真#
C. 饱和失真#
D. 截止失真
【单选题】
___，一般有安全色、几何图形和图形符号构成，其目的时要引起人们对危害因素的注意，预防生产安全事故的发生。
A. 安全警示标志#
B. 危险标志#
C. 产品标志#
D. 特种标志
【单选题】
___，是指容易发生人员伤亡事故，对操作者本人、他人及周围设施的安全有重大危害的作业
A. 危险作业#
B. 特种作业#
C. 登高作业#
D. 特殊作业
【单选题】
在煤矿安全监管执法与决策系统中，不属于安全信息功能的是___ 。
A. 安全监控报警#
B. 人员管理报警#
C. 产量数据统计#
D. 产量监控报警
【单选题】
___工作面的防突措施包括预抽煤层瓦斯、排放钻孔、金属骨架、煤体固化、水力冲孔或其他经试验证明有效的措施。
A. 井巷揭煤#
B. 煤巷#
C. 岩巷#
D. 半煤岩巷
【单选题】
___方法不能减少巷道通风阻力
A. 采用梯形断面巷道#
B. 保持巷道连接部光滑#
C. 断面逐渐变化#
D. 清理巷道中不用的障碍物
【单选题】
___以下的煤层厚度叫薄煤层。
A. 1m#
B. 1.3m#
C. 1.5m#
D. 1.8m
【单选题】
___可用来扑灭电气设备火灾。
A. 水#
B. 砂子、岩粉#
C. 湿布#
D. 石头
【单选题】
___可采取超前钻孔预抽瓦斯、超前钻孔排放瓦斯、注水湿润煤体、松动爆破或其他经试验证实有效的措施。
A. 采煤工作面#
B. 煤巷掘进工作面#
C. 岩巷掘进工作面#
D. 掘进工作面
【单选题】
___必须对低压漏电保护进行1次跳闸试验。
A. 每班#
B. 每天
C. 经常#
D. 每周
【单选题】
___必须最后离开爆破地点，并必须在安全地点起爆。
A. 班组长#
B. 爆破工#
C. 瓦斯检查工#
D. 安检工
【单选题】
___发生火灾时，应进行区域性反风。
A. 进风井口#
B. 井底车场#
C. 进风大巷#
D. 工作面进风巷
【单选题】
___对事故隐患和安全生产违法行为，均有权向负有安全生产监督管理职责的部门报告或者举报。
A. 单位领导和群众#
B. 安全管理人员和技术人员#
C. 任何单位或者个人#
D. 工人
【单选题】
___应为接触职业病危害因素的从业人员提供符合要求的个体防护用品，并指导和督促其正确使用。
A. 煤矿企业#
B. 当地政府#
C. 国家#
D. 国有企业
推荐试题
【多选题】
What two IT infrastructure components are virtualized by vSphere Essentials? (Choose two.)___
A. Networks
B. Applications
C. Storage
D. Management
【多选题】
When attempting to access a virtual machine, an administrator is unable to login using the vSphere credentials. What two options are probable causes of the authentication failure? (Choose two.)___
A. The vSphere credentials have not been granted permissions.
B. The vSphere credentials are granted read-only permissions.
C. The vSphere credentials are granted no-access permissions.
D. The vSphere credentials are not a member of the local administrator group.
【多选题】
An administrator is performing a scripted installation of ESXi 6.x. In which three locations does the script need to be? (Choose three.)___
A. PXE Server
B. HTTPS
C. FTP
D. NFS
E. VVOLs Datastore
【多选题】
In order for a company to meet regulatory requirements, all ESXi 6.x Hosts must be configured to direct logs to a syslog server. What are two ways ESXi hosts can configured for this action? (Choose two)___
A. Use the esxcli system syslog command.
B. Edit them in the ESXi host Advanced System Settings.
C. From the Syslog collector user interface of the Web Client.
D. Syslog logging is not available for
E. SXi Hosts.
【多选题】
Which three actions can be executed when an alarm is triggered? (Choose three.)___
A. Send an email.
B. Send an SNMP trap.
C. Run a script or command.
D. Run an Orchestrator workflow.
E. Send a trigger to syslog.
【多选题】
An administrator is attempting to power on a virtual machine, but is unable to do so. Which two reasons are probable causes of the failure? (Choose two.)___
A. Storage access to the virtual machine swap file has been lost.
B. One of the virtual machine VMDK files is locked.
C. Virtual machine is running CentOS 7.0 64-bit.
D. Virtual machine has Hyper-Threading enabled.
【多选题】
An administrator has configured a host profile so that ESXi 6.x hosts will point to the corporate NTP server for time synchronization. The NTP server is located at 10.0.30.213, but time has not been synchronized properly across the ESXi hosts. The administrator reviews Host Profile settings as shown in the Exhibit. Which two steps are required to resolve the issue? (Choose two.)___
A. Correct the NTP server IP address.
B. Check the host for host profile compliance.
C. Remediate the host based on the updated host profile.
D. Change the NTP server to the FQDN as IP Addresses are not supported.
【多选题】
An administrator is attempting to migrate a large Hadoop virtual machine using vMotion. The administrator notices a delay when the machine is quiesced. The Hadoop virtual machine is processing many transactions a second to an in-memory database. Which two actions would help reduce the amount of time needed to perform a vMotion on this virtual machine? (Choose two.)___
A. Use multiple NICs for the vMotion vmkernel port.
B. Use a 10Gbps Network card for the vMotion vmkernel port.
C. Add an additional management network to help transmit the data quicker.
D. Disable Fault Tolerance before performing the vMotion.
【多选题】
An administrator is installing a new network card in an ESXi 6.x host that is part of a vSphere cluster. When the host is placed into maintenance mode, the vSphere Web Client displays the progress bar at 2% for over 30 minutes. Which two are likely reasons for this occurrence? (Choose two.)___
A. Maintenance mode is unable to migrate all virtual machines from the host.
B. There is a large number of virtual machines that must be migrated from the host.
C. VMware High Availability is in the process of reconfiguring the cluster.
D. Each virtual machine on the
E. SXi host must be reconfigured to recognize the new adapter.
【多选题】
Which two events happen when Distributed Resource Scheduler (DRS) is disabled? (Choose two.)___
A. The cluster's resource pool heirarchy and affinity rules are re-established when DRS is turned back on.
B. The cluster's resource pool hierarchy and affinity rules are not re-established when DRS is turned back on.
C. The cluster's resource pools are removed from the cluster.
D. The cluster's resource pools are removed from the cluster and assigned to the hosts.
【多选题】
Which two networking connection types can be configured on a virtual switch? (Choose two.)___
A. Virtual machine portgroups
B. VMkernel services (such as NFS, iSCSI, or vMotion) to the physical network
C. Web services over the Management Network
D. NFS and FCoE storage services
【多选题】
An administrator creates a DRS cluster of eight ESXi 6.x hosts. There are 10 virtual machines balanced across the hosts. An attempt to place the first host into maintenance mode fails. What are two reasons that the host failed to enter maintenance mode? (Choose two.)___
A. The DRS cluster Automation Level is set to Partially Automated mode.
B. One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Should run on hosts in group.
C. One of the virtual machines on the ESXi Host entering maintenance mode is configured with a DRS Host affinity rule Must run on hosts in group.
D. One of the virtual machines on the
E. SXi Host entering maintenance mode is configured with an individual Automation Level set to Partially Automated.
【多选题】
When modifying a vApp, which two vSphere entities can be added? (Choose two.)___
A. A resource pool
B. A network pool
C. A vApp
D. A folder
【多选题】
From which two locations in the inventory hierarchy can you deploy a virtual machine using a template? (Choose two.)___
A. Directly from the template.
B. From a compute resource.
C. From an existing virtual machine.
D. From a Datastore.
【多选题】
A company has decided to implement Virtual SAN within their vSphere 6.x environment. The Virtual SAN cluster will be composed of three ESXi 6.x hosts that are on the Virtual SAN Ready Node list. Each ESXi host includes: <Two SAS Controllers that support Passthrough Mode> < Four Solid State Drives (SSDs) 1TB in size each> <20 SAS Magnetic Disks (MDs) 1TB in size each> <The SSDs and MDs are evenly split between the two SAS controllers>. The company will pilot a Virtual SAN cluster utilizing VMware best practices while maximizing storage capacity. The Virtual SAN cluster will use Manual Mode. Which two Disk Group configurations would meet the stated configuration requirements? (Choose two.)___
A. 4 disk groups with 1 SSD and 5 MDs each
B. 2 disk groups with 1 SSD and 7 MDs each
C. 2 disk groups with 2 SSDs and 7 MDs each
D. 2 disk groups with 1 SSD and 10 MDs each
【多选题】
A physical Windows 2008 R2 Server is converted to a virtual machine using VMware vCenter Converter. Upon completion of the conversion and subsequent power on operation, the virtual machine fails to boot and the message below is observed in the Console of the virtual machine: <STOP 0x0000007B INACCESSIBLE_BOOT_DEVICE>. Which two potential issues may be causing this boot failure? (Choose two.)___
A. An incorrect SCSI controller was selected during conversion.
B. Incompatible software drivers were migrated into the virtual machine from the source machine.
C. The vmdk file backing the virtual machine was thick provisioned.
D. A snapshot was taken immediately after the conversion completed.
【多选题】
An administrator is configuring the Failover Order option on a vSphere Distributed Switch. Which two options should be used with IP-hash load balancing? (Choose two.)___
A. Active Uplinks
B. Standby Uplinks
C. Unused Uplinks
D. Override Failover Order
【多选题】
An administrator is configuring the Maximum Transmission Unit value on a vSphere Distributed Switch. Which two options are typical values for ESXi networking? (Choose two.)___
A. 1492
B. 1500
C. 9000
D. 9089
【多选题】
Which two configurable options apply to both virtual machine CPU and memory allocation? (Choose two.)___
A. Reservation
B. Shares
C. Resource Pool
D. Reserve All
【多选题】
When attempting to power on a Virtual Machine you observe the following error: <Cannot open the disk '/vmfs/volumes/volume/vm/vm-000002.vmdk' or one of the snapshot disks it depends on.> Which three actions will be the best solutions to address this problem? (Choose three.)___
A. Verify that the virtual machine's disk files are present.
B. Investigate the host and virtual machine log files.
C. Verify the vmdk descriptor files and if required, recreate them.
D. Delete the disk file preventing the power on operation.
E. Migrate or register the virtual machine to a different host.
【多选题】
An administrator has been tasked with enabling High Availability ___ on a cluster in a vSphere 6.x environment with default settings. The cluster configures properly and there are no errors. The next day when powering on a virtual machine, an error is presented: <Not Enough Failover Resources>. Which three scenarios are likely causes of this error message? (Choose three.)(CDE)
A. The default VM Monitoring Sensitivity is set too high.
B. There are not enough datastore heartbeat datastores configured by default.
C. The default slot size in the cluster is set too high.
D. There are virtual machines with large CPU reservations.
E. A host is in maintenance mode for a replacement of a failed Hard Drive.
【多选题】
vMotion can be performed between which three physical boundaries? (Choose three.)___
A. Between two vCenter Server Systems
B. Between two vSphere Distributed Virtual Switches
C. Between two vCenter Server Datacenter objects
D. Between two VMware NSX Layer 4 segments
E. Between two NFS datastores
【多选题】
An administrator configures vSphere Replication for a virtual machine and enables multiple point in time (PIT) instances under the recovery settings in the Configure Replication wizard. Which two statements are correct for vSphere Replication with multiple point in time instances enabled? (Choose two.)___
A. vSphere Replication retains a number of snapshot instances of the virtual machine on the target site based on the retention policy that you specify.
B. vSphere Replication uses the virtual machine's snapshot instances to define the target site Point in Time instance based on the retention policy that you specify.
C. vSphere Replication does not support virtual machines with snapshots.
D. vSphere Replication supports virtual machines with snapshots.
【多选题】
An administrator is virtualizing a physical application server and adding it to an existing multi-tiered vApp. The application license is currently tied to the physical NIC's MAC address, so the administrator needs to ensure the license will function properly in the virtual machine. Which two actions can the administrator take to satisfy this task? (Choose two.)___
A. Set the MAC address for the vNIC in the guest operating system.
B. Install the physical server's NIC into the ESXi host.
C. Configure the MAC address for the vNIC using the vSphere Web Client.
D. Assign the physical server NIC's MAC address in the vSphere Distributed Switch.
【多选题】
Which two Fibre Channel zoning options are supported with vSphere 6.x? (Choose two.)___
A. Single-Initiator
B. Single-Initiator-Single-Target
C. Multiple-Initiators-Single-Target
D. Multiple-Initiators-Multiple-Targets
【多选题】
An administrator is attempting to remove an ESXi 6.x host from a vSphere Distributed Switch (vDS). When the administrator attempts to remove the host, the following error is observed: <The resource '16' is still in use.> What three steps are needed to successfully remove the host from the switch? (Choose three.)___
A. Select Manage Ports on the vDS for the host.
B. Locate all ports currently in use on the vDS for the host.
C. Migrate or delete any vmkernel or virtual machine adapters associated with the switch.
D. Remove all network cards from the switch before trying to remove the host.
E. Create a standard switch for everything to be automatically be migrated to.
【多选题】
Which two Virtual SAN related actions might start resynchronization of virtual machine objects? (Choose two.)___
A. Editing a virtual machine storage policy to increase the number of replicas.
B. Editing a virtual machine storage policy to reduce the number of replicas.
C. Editing a virtual machine storage policy to increase the number of disk stripes.
D. Editing a virtual machine storage policy to reduce the number of disk stripes.
【多选题】
An administrator is troubleshooting basic network connectivity issues. Which two scenarios are potential issues that this administrator might face? (Choose two.)___
A. The vSwitch is not attached to the correct physical network.
B. The portgroup is not configured to use correct VLAN.
C. Traffic shaping is configured incorrectly.
D. Jumbo frames is configured incorrectly.
【多选题】
Which three items should be validated prior to installing ESXi 6.x? (Choose three.)___
A. Remote Storage has been disconnected.
B. Installation media is available.
C. Server hardware clock is set to UTC.
D. Storage has been partitioned with a VMFS volume.
E. Network cards have been setup to use Jumbo
F. rames.
【多选题】
An administrator is performing an interactive installation of ESXi 6.x. Which three options are available for installation? (Choose three.)___
A. DVD
B. USB
C. PXE
D. Scripted
E. Auto Deploy
【多选题】
After installation of a host in your test environment, you need to move it to production. The only major change that needs to be made is that the hostname of the server needs to change. What are two ways that an administrator can change the host name without editing configuration files on the host directly? (Choose two.)___
A. Login to the Direct Console User Interface and change it from here.
B. Edit the Default TCP/IP Configuration from the vSphere Web Client.
C. Use the Ruby vSphere Client to send a script to the ESXi host that updates the hostname.
D. Update the information in DNS and the
E. SXi host will automatically update with these changes.
【多选题】
An administrator has unsuccessfully attempted several times to install an Operating System inside a virtual machine. The administrator finds that the installation fails at random intervals. Which two actions can be taken to resolve this issue? (Choose two.)___
A. Verify the md5sum and if invalid, download the installation files again.
B. Attempt the installation an additional time.
C. Attempt to use a different installation media or installation method.
D. Create a new virtual machine and attempt the installation with the existing media.
【多选题】
VMware tools is failing to install on a Microsoft Windows virtual machine. What are two possible situations that would prevent the installation? (Choose two.)___
A. The VMware tools installation media is corrupt.
B. The incorrect Operating System was selected in the virtual machine options.
C. The software prerequisites have not been installed.
D. The prerequisite services have not been started.
【多选题】
As part of a multisite Single Sign-On (SSO) deployment what two steps are required to ensure that a change to one Single Sign-On instance is propagated to the other instances? (Choose two.)___
A. Schedule a Replication Task on the primary instance
B. Select the first instance during the installation of subsequent instances
C. During the installation of each instance choose Linked-Mode
D. Enable Synchronize to Active Directory on each instance
【多选题】
You need to add an object to an existing vApp using the vSphere Web Client. How is this accomplished?___
A. Create an Object Inside the vApp.
B. Add an Object to a vApp.
C. Add an Object to the
D. atastore the vApp is located in.
【多选题】
Which three steps must be taken to use vSphere Update Manager 6.x to upgrade an ESXi 5.5 host to vSphere 6.x? (Choose three.)___
A. Download an ESXi Image.
B. Configure the vSphere Update Manager Download Service.
C. Create a baseline and attach it to the ESXi Host.
D. Scan the vCenter Content Library for the
E. SXi Image.
【多选题】
Which two options would allow a database administrator, with no access to the vSphere infrastructure, to connect to a virtual machine? (Choose two.)___
A. Use the Virtual Machine Remote Console (VMRC).
B. Use Remote Desktop Protocol (RDP) to connect.
C. Ask the vSphere administrator to grant permission to access the console through vCenter Server.
D. Ask the vSphere administrator to grant permission to access with the Horizon View Direct Connect Client.
【多选题】
Which three are architecture components of vRealize Operations? (Choose three.)___
A. Identity Server
B. Administrative Server
C. Analytics Server
D. Database Server
E. Connection Broker
【单选题】
金克拉金克拉撒旦蒂萨里大儿童家爱丽丝打开就撒开绿灯技术的（）
A. 手动阀手动阀
B. 撒旦
C. 反对法
D. 第三方
【单选题】
金克拉金克拉撒退热贴开绿灯技术的（）
A. 是否
B. 阿斯顿
C. 撒旦
D. 感到反感
